Using Heat to Kill the Coronavirus

Reviewed and edited by Tod Cooperman, M.D. Tod Cooperman, M.D.
Initial Posting: 4/8/2020    Last Update: 8/11/2020

Does heat kill coronavirus (COVID-19)? Can it disinfect face masks and packages?
Does Heat Kill Coronavirus? -- Women Receiving Food Delivery
If used properly, moderate or high heat can be used to "kill" coronavirus, inactivating the virus so that it is no longer infectious. However, in many cases this may be more time-consuming than other methods such as chemical disinfection (with disinfecting wipes or sprays) and there is often no need to disinfect packaging at all if you can just remove the packaging, dispose of it (preferably by recycling), and then disinfect your hands by washing with soap and warm water or using another disinfection method. Furthermore, the FDA has stated that "...there is currently no evidence of human or animal food or food packaging being associated with transmission of the coronavirus that causes COVID-19." Although the agency notes "...if you wish, you can wipe down product packaging and allow it to air dry, as an extra precaution."

Heating kills coronavirus

Heat is very effective at sanitizing and disinfecting objects from coronavirus. If anyone tells you that coronavirus is resistant to heat, they're wrong. In fact, the SARS-CoV-2 virus that causes COVID-19 may be even more sensitive to heat than the earlier SARS-CoV virus. Experiments done in China in 2002 with SARS-CoV in culture medium (Duan, Biomed Env Sci 2003) showed that coronavirus became undetectable after 30 minutes when heated to a temperature of 167°F, but recent tests with SARS-CoV-2 in Hong Kong showed that it became undetectable after just five minutes at only 158°F (70°C). The time required to kill SARS-CoV-2 increased as the temperature was reduced, such that the time by which it was undetectable increased to 30 minutes at 132°F (56°C), two days at 98.6°F (37°C), and two weeks at 71.6°F (22°C). At 39°F (4°C) the virus remained detectable at two weeks when the experiment ended (Chin, Lancet 2020).

This suggests, for example, that if you purchase take-out food and wish to disinfect the container itself of coronavirus (as well as keep your food warm), you can simply place the container in a warm oven or warming drawer for a period of time, such as at 150°F (65°C) for 60 minutes (giving it ample time to heat up) to disinfect it. Just be sure it is not directly exposed to a heating element so as not to pose a fire hazard. Most plastic and paper containers are stable for short periods at up to 200°F (93°C). 

Theoretically, heating a face mask this way may also disinfect it. Moist heat may be better than dry heat. One way to do this, as explained by the Department of Homeland Security Science and Technology Directorate (S&T), is to use a multicooker or electric pressure cooker that has a sous vide function or equivalent capability to set the time to 30 minutes and the temperature to 149°F (65°C), placing the mask on a rack to keep the mask out of the water (binder clips can be used to elevate the rack). The bottom of the pot should be covered with ½ inch of water, and the mask should be placed in a paper bag and the bag stapled closed, before placing on the rack. Up to three masks can be nestled together in one bag. When the cycle is over, the masks should be removed and allowed to dry (about one hour should be sufficient). A complete instructional video is available on the Department of Homeland Security S & T website. A study by researchers at Stanford University found that heating N95 masks (known as respirators) at 167°F (75°C) for 30 minutes (at 85% relative humidity) did not compromise the masks, even after 20 cycles — although these researchers have subsequently cautioned that contaminated masks should not be brought into homes. (If you use an N95 respirator, you may want to watch a video from the New England Journal of Medicine that instructs health care workers on how to properly put on, take off, and test the fit of such masks and other personal protective equipment.)

Another way to use an electric cooker to decontaminate N-95 respirators is to place a towel inside the cooking pot with the respirator laying on the towel (avoiding direct contact between any part of the respirator and the pot) and heating the mask to 212°F (100°C) for 50 minutes -- which requires heating the pot to about 250°F to 300°F (120° to 150°C). The University of Illinois researchers who developed this process (and uploaded a demonstration video on YouTube) found that respirator filtration and fit were not compromised after 20 cycles of this dry heat treatment (Oh, Env Sci Tech Letters 2020).

A U.S. government laboratory heated SARS-CoV-2-contaminated N95 mask material in a dry oven at 158°F (70°C) and found that virus was undetectable at 50 minutes, but they also found two cycles of this dry heating caused the material to lose some integrity (possibly suggesting that some humidity during heating may be beneficial) (Fischer, medRxiv, 2020 — preprint).

These same government researchers found that ultraviolet light (UVC at 0.005 mW/cm2) could achieve the same antiviral effect as heat with less impact on mask integrity but required about 60 minutes and this did not factor in additional time to properly irradiate curved surfaces of the mask. They determined that vaporized hydrogen peroxide (requiring a special, enclosed incubator) was the fastest and least damaging method of decontamination, taking only 10 minutes. Spraying ethanol to saturate the mask material was a bit faster at deactivating virus but caused the greatest reduction in mask integrity (Fischer, medRxiv, 2020 — preprint).

You should not soak N95 or surgical masks in disinfectants such as alcohol or other liquids as this can compromise their electrostatic charge (reducing their filtering capability) and fit (Interview with R. Shaffer, JN Learning 2020). Researchers at Stanford University found that immersing N-95 mask material in 75% ethanol or spraying with a household chlorine bleach solution (2% sodium hypochlorite) decreased the filtration efficiency (due to loss of electrostatic charge) to unacceptable levels after just one treatment, from about 96% to 56% and 73%, respectively.

Steam treatment (material placed 6 inches above a glass containing boiling water for 10 minutes) was effective if used once, but after five treatments filtration efficiency fell below acceptable levels (85%) (Liao, ACS Nano 2020).

Note that washing cloth face masks in a washing machine should suffice to disinfect them, according to the CDC. The agency also cautions not to touch your eyes, nose, and mouth when removing cloth coverings, and to wash hands immediately after removing. 

Coronavirus lasts longer on certain surfaces, particularly surgical masks!

The Hong Kong researchers noted above also placed a small amount of the SARS-CoV-2 on a variety of surfaces at room temperature (at 65% relative humidity) to see how long the virus would last before becoming undetectable. On tissue paper and regular paper it became undetectable within just 3 hours. On cloth and on paper money, it lasted 2 days. Surprisingly and disturbingly, it lasted longest on the outer layer of a surgical mask: Virus was detectable on the mask at day 7 (although at only 0.1% of its original level), which was also how long it lasted on plastic and stainless steel.

Microbiologists who placed coronavirus samples on the interior surfaces of a car, including carpeting and plastic parts, found that viral concentrations were reduced by greater than 99% within 15 minutes when the interior air was heated to 133°F (56°C), raising surface temperatures to 120°F (Unpublished study reported in The New York Times, May 30, 2020).

Don't directly refrigerate or freeze — it keeps the virus infectious

Studies with coronaviruses noted above and by others (Kampf, J Hosp Infect 2020) indicate that cold temperatures help preserve it and keep it infectious. Consequently, you should not place a recently purchased food container directly into a refrigerator or freezer and you should not "quarantine" a recently received package in a cold cellar or cold garage, as this will preserve coronavirus and could keep it infectious for days. Freezing can preserve coronavirus for years (WHO, COVID-19 Situation Report 32, 2020). The good news is that the coronavirus won't linger quite as long on surfaces and in the air in warm summer weather as it does in the winter, although this won't make much of a difference should an infected person cough near you. 

How effective are disinfectants against coronavirus?

The Hong Kong researchers also showed that common disinfectants were effective in killing SARS-CoV-2. The virus was undetectable after 5 minutes of exposure to household bleach (at a concentration of 1:49 or 1:99), ethanol (70%), povidone-iodine (7.5%), chloroxylenol (0.05%), chlorhexidine (0.05%) and benzalkonium chloride (0.1%). Fifteen minutes were required for the virus to be undetectable when exposed to a hand soap solution. The researchers only checked at 5 and 15 minutes, so it is possible that less time is necessary, but as we don't know the minimum time for disinfection, it would seem prudent to allow disinfectants a few minutes on surfaces before wiping them off. For the latest list of disinfectants that meet the U.S. EPA's criteria for use against SARS-CoV-2, see the EPA's "List N." There is a search box to quickly look up a product or ingredient and you should view the "Contact Time" to see how long each disinfectant must remain wet on a surface. The list includes ready-to-use liquids, dilutable liquids, and wipes. (Note that products on List N have not been tested specifically for SARS-CoV-2, but have demonstrated efficacy against a similar coronavirus or a harder to kill virus.)

Be careful when using and storing chemical disinfectants

Calls to poison control centers increased sharply in March 2020 due to disinfectants (CDC, 2020). Cases have included a woman who developed difficulty breathing after mixing 10% bleach with vinegar and water to wash her produce and a child was found unresponsive after consuming ethanol-based hand sanitizer. The CDC advises that "users should always read and follow directions on the label, only use water at room temperature for dilution (unless stated otherwise on the label), avoid mixing chemical products, wear eye and skin protection, ensure adequate ventilation, and store chemicals out of the reach of children."

Hand sanitizer
When soap and water are not available, the CDC advises using hand sanitizer containing at least 60% alcohol (typically hand sanitizers contain alcohol in the form of ethanol or isopropyl). It also notes that benzalkonium chloride, an ingredient in some hand sanitizers, has "less reliable activity against certain bacteria and viruses than either of the alcohols." A recent review of studies suggests that most alcohol-based hand sanitizers are effective at inactivating coronaviruses in general, although tests of their effects on SARS-CoV-2, the coronavirus that causes COVID-19, were not included (Golin, Am J Infect Control 2020). The researchers also emphasized the importance of using an adequate amount of hand sanitizer, which a study among adults found should be at least ½ teaspoon or more to get complete coverage, but one pump from a dispenser provides only about half of this amount: Two pumps are needed to achieve better coverage. Hand sanitizers used in the study included Purell Advanced Instant Hand Sanitizer and Purell Advanced Instant Hand Sanitizer Foam, each containing 70% ethanol (Kampf, BMC Infect Dis 2013).

[Note: On June 19, 2020, the FDA warned consumers not to use hand sanitizers manufactured by Eskbiochem after two of the company's products were found to contain methanol. Methanol is toxic and can cause serious illness or death when absorbed through the skin or ingested. See the warning for more details, including a list of nine Eskbiochem hand sanitizers (sold under various brand names).]

Disinfecting wipes
If you use a disinfecting wipe on a surface that may come in contact with food or be placed in the mouth (like a baby bottle), be sure to rinse the surface with water and dry after wiping. A Clorox spokesperson told ConsumerLab that "Clorox Disinfecting Wipes can disinfect plastic packaging that is non-porous. Packaging should not have any holes that would allow the disinfectant to make direct contact with food. The wipes should never be used directly on food and should not be used on paper or cardboard packaging." As some consumers have wondered if the wipes can be used on microwaveable "steam" bags (as for steaming vegetables), it would seem that the wipes can be used on the front and back surfaces but perhaps not at the ends and seams where steam vents are placed.

Clorox wipes have a shelf life of one year from the date of manufacture, and Lysol indicates two years for its wipes.

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Isabel20203   June 17, 2020
Do you have any information on the time required to disinfect produce at the boiling point of water?

What I've been doing with blueberries and cherries, for example, is to put them in a sieve, put the sieve in a bowl, and cover them with boiling water. I remove the berry-containing sieve after about half a minute because I don't want to destroy any healthy ingredients in the berries. Can you improve on this method?   June 24, 2020
Please see the CDC's guidelines for washing fruits and vegetables:

Bruce20083   May 31, 2020
I also read last week that because heat kills the Coronavirus, Ford is doing a software update to heat the interiors of police cars to 133 degrees for 15 minutes to kill it. This led me to consider the heat from a sauna and if breathing the heated air is beneficial since this is a respiratory infection? For example, could sitting in an infrared sauna at 133 degrees or higher and breathing the heated air for 15 minutes or some other period of time act as a therapy?   June 3, 2020
We've added information about the study on heating cars in the answer above.

While heat has been shown to kill the coronavirus on surfaces, there is no evidence that using a sauna can prevent COVID-19 or kill the virus in the body. Although somewhat different than a sauna, the World Health Organization states on it's COVID-19 Myth busters page ( that hot baths will not prevent infection:
"Taking a hot bath will not prevent you from catching COVID-19. Your normal body temperature remains around 36.5°C to 37°C, regardless of the temperature of your bath or shower. Actually, taking a hot bath with extremely hot water can be harmful, as it can burn you."

Isabel19991   May 21, 2020
If you're going to cook the food, what's the point of disinfecting the packaging? I remove and dispose of the packaging with gloves on, then wash my hands and cook the food.

John19983   May 20, 2020
What is your thought ~ if you are familiar ~ with LOTUS food sanitizer? I searched but I could not find any useful information.
I'm going to farmer's market to buy mostly our veggies. They are amazingly fresh.
What do you think that machine would kill Covid 19?

Thank you for taking my questions.   June 3, 2020
Unfortunately there does not appear to be enough information available about this product to comment on its effectiveness.

Susan19966   May 20, 2020
We disinfect hard packages including those waxy cardboard frozen food packages by rubbing all with a wet bar of hand soap and then putting them in a plastic bag so the soap won't get on fridge or freezer. Soap is supposed to dismantle the virus envelop. Soft frozen plastic food bags as long as no holes get a quick dunk in a very soapy ( dish detergent) bowl of cool water, dried off, and transferred to another bag for freezer storage. Does this procedure seem reasonable? We don't have a lot of chemical disinfectant wipes or alcohol at this time.   May 20, 2020
Wetting a towel with warm soapy water, wiping objects down, and letting them dry is probably sufficient. Just wash your hands when you're done.

Marshelia19965   May 20, 2020
I haven't read any information anywhere about meal delivery protocols. I subscribe to a meal delivery service that sends me 3 meals a week to prepare and cook. It comes in a cardboard box filled with frozen packets to keep the food cold. The meats are in individual plastic packages packed between frozen packets. The vegetables, spices, sauces etc., are packed in brown paper bags for each meal. Veggies are often whole and loose in the bag (onion, tomato, etc.). Spices, sauces, chopped veggies are individually packaged in sealed plastic. I receive 1 box each week. It takes 2-3 days shipping time for the box to reach my home. I have been wiping down the big box to open it but assume that anything inside the box should be safe to touch, place in my refrigerator. I always rinse whole vegetables before chopping/cooking. Am I taking enough precautions? Thanks for your article and site.   May 20, 2020
Since the contents arrive cold/frozen, should there be virus on the packaging, it would likely remain viable. So if you want to be very diligent, as you remove the foods from the packets and bags and disposing of them, just wash your hands well. If you are putting these individually in your refrigerator, you might want to disinfect the surface of the packets/bags (if they are non-porous) first.

Don19960   May 20, 2020
Does anyone have experience with disinfecting with an ozone generator?   May 20, 2020

Stephanie19954   May 20, 2020
I have a N95 has an outer shell and the inside is a changeable N95...I have a spray bottle I keep on the counter with straight alcohol...what ever I can get 70 or 99% and use it straight...spray the counter tops for clean groceries and even spray my doesn't seem to bother the fruit at all and I wash it off and dry prior to putting away...I think it may even last longer...I wipe down all packaging with the spray and then dry after about 10minutes. This has worked well for hubby is high risk and we have stayed healthy...I Also spray the gutter mask with the straight alcohol and let air dry...I have sanitizer in the car...all good so far...Any comments are appreciated ...I make my own wipes with cloths, or gauze and alcohol in a baggie...stays good for ...well since stay at home mandate!!   May 20, 2020
Please see the information above about soaking and/or spraying N95 masks with liquids such as alcohol.

Jeffrey19948   May 20, 2020
I have ten M95 masks that I used to use for yard work to avoid moldy leaves, etc. Now, they do Covid duty as protection when my wife or I (seniors) shop for food. I've taken to using a mask and then placing it on a shelf with a date of use. That way, a "used" mask has been sitting for several weeks before being used again as we rotate through them.. BTW, these shopping forays are quite brief and in stores that limit numbers entering. Does this seem a to be sensible strategy or am I missing something?   May 20, 2020
As long as they are in a room that is at least at room temperature, that seems reasonable.

Brenda19935   May 17, 2020
I read that an N95 mask could be hung up
For 5 days (like in your garage) after wearing and Covid19 will die and the mask could be cleaned if needed and then worn again. Could you verify this please.   May 28, 2020
If your garage is at least room temperature, that should work fine (the virus survives longer in cooler temperatures, as discussed in the answer).

Kathleen19932   May 17, 2020
The information about heat killing coronavirus says that at 71.6 degrees, the virus remained detectable for two weeks. That is approximately room temperature. How is this possible, when we are being told (from many other sources) that the virus lives on surfaces such as cardboard, metal, and plastic, for much less time than two weeks (usually no more than three days)?   May 29, 2020
The difference in the survival time of the virus at similar temperatures is due to the surface and condition in which it was tested (a culture medium vs a surface such as cardboard).

Gale 19927   May 17, 2020
Will putting N-95 and other masks in direct sunlight kill virus effectively? I've been sunning mine, but need to know if it's a safe method.   May 20, 2020
There is not enough information at this time to say. In preliminary research, simulated sunlight was very effective against SARS-CoV-2 on non-porous surfaces (see for details). However, differences in temperature, humidity, the mask material and the shape of the mask could affect the results.

Bill19919   May 15, 2020
How long does covid-19 remain on carpet and is it safe to vacuum carpet. I imagine it would be too dangerous to have a carpet cleaning company come into our home because most likely the equipment most likely would bring in covid-19 from other homes.   May 20, 2020
As noted in the answer above, the virus that causes COVID-19 appears to survive longer on hard, non-porous surfaces such as plastic and stainless steel (7 days) than on soft or more porous surfaces such as cloth (2 days), but currently there does not appear to be research on how long it survives on carpet. The CDC offers guidance for cleaning and disinfecting soft, porous surfaces such as carpeted floors, rugs and drapes

Cindy19916   May 14, 2020

What is the best way to clean fresh fruits and vegetables?

I've heard so many things I'm not sure what is the best and safest.

Thank you!   May 14, 2020
The FDA recommends the following: "Before eating, rinse fresh fruits and vegetables under running tap water, including those with skins and rinds that are not eaten. Scrub firm produce with a clean produce brush." (See

Michael19903   May 13, 2020
Does the alcohol in hand sanitizer evaporate at higher temperatures? Such as leaving a bottle in the car even though it is sealed.   May 14, 2020
The alcohol in hand sanitizers can evaporate if the bottle is left open and exposed to heat, so the bottle should not be left open during warm weather or in direct sun (such as in a car during warm weather).

According to Purell's website, its products "should be stored at temperatures from 0-43 C (32-109.4 F) for the product shelf life and expiration." ([FAQ])

Stan19898   May 13, 2020
Two comments
Using a disinfectants such as (spray)Lysol is not harmless in and of itself. I have gotten skin rashes in doing so, when trying to disinfect doorknobs in my building, despite using hand coverings. The stuff still gets into the aor. We breathe it. It gets on our skin. It's not all good.

Secondly with regard to the FDA statement that "there is currently no evidence of human or animal food or food packaging being associated with transmission of the coronavirus that causes COVID-19" :
It is extraordinarily difficult to decisively link such everyday exposures in one's life to contracting the virus..The fact that there is "no evidence" (even though the virus remains on surfaces for varying periods of time ) does not prove that there is nothing to worry about in this regard. There is so much we do not know about this new virus, its transmission, its immunity and its possible aftereffects.

Alison20302   July 5, 2020
I absolutely agree with what you said about "not likely to get it from food". They have no way to know that and I think it's ridiculous for anyone to make that statement. I will continue to disinfect all food that I have delivered.

Cindy19889   May 13, 2020
Thank you for all your hard work to keep us up to date and informed.

I am concerned about putting cloth masks - potentially contaminated with Coronavirus in the washer and dryer. Why would this disinfecting process work? In the Stanford study mentioned in the above article it says they don't advise bringing contaminated masks into the home.

Maybe having a lot of masks and letting them sit at room temp for days before wearing again - thus avoiding the washer and potentially cross contamination altogether?? Would this work to have a virus free mask?

Thank you!   May 13, 2020
If you wash a cloth mask in a washing machine with warm or hot water and detergent, there is no risk, as far as we are aware, of contaminating other items in the laundry. It will effectively disinfect the mask. Letting them sit a room temperature for several days should also work.

Kathleen19847   May 10, 2020
Why don't I see hydrogen peroxide in your list of acceptable disinfectants for Covid-19? I am sure that I have seen it listed previously in other sources.   May 11, 2020
In the answer above, we mention several disinfectants that were tested on SARS-CoV-2 in the study by researchers Hong Kong. The answer also provides the link to the EPA's "List N" ( which list many more disinfectants that meet the agency's criteria for use against SARS-CoV-2, including hydrogen peroxide.

Mary19843   May 10, 2020
I am curious when you refer to studies in which coronavirus is "detectable" at certain points in time (such as on surgical masks), whether that means it is actually viable, or just some recognizable traces are present that could not infect anyone?   May 11, 2020
The disinfection techniques that reduce the virus to undetectable levels have generally shown reductions of at least 1,000-fold and to the point where virus can no longer be cultured from the sample. Is it necessary to get that low to avoid infection? It may not be, but it's hard to say at this time.

Maxine19787   May 3, 2020
I use an ozone cleaner for my CPAP machine. Can I use it to clean my face mask, etc.? Will it work against the Corona virus?   May 4, 2020
Please see our information about ozone devices and COVID-19 here

MaryLee19767   April 30, 2020
ConsumerLab, thank you so much for this website! Are 70% alcohol wipes effective in disinfecting the outside of food containers (ex. carton of milk)? If so, how long should the container sit before being placed in the refrigerator?   April 30, 2020
We are glad to hear you are enjoying ConsumerLab. 70% alcohol is considered effective for disinfecting the SARS-CoV-2 virus ( The EPA's list of recommended disinfectants (linked to in the answer above) notes that isopropyl alcohol should sit for 5 minutes.

Diane 19722   April 28, 2020
If you wash your cloth masks in cold or warm water and hang dry would then steaming them with an iron kill the virus?

Carol19716   April 28, 2020
THANKS so much for including the FDA message (that there is no proof that wiping down our groceries helps) . . . I saw that tweet when it first came out.
**I also distinctly remember hearing audio of Dr. Fauci, answering a woman during an early Q&A back in March, stating that the titer (concentration) of virus on our delivered mail is much too low for concern!!!

Anthony19699   April 26, 2020
Is it sufficient for take out food to REACH a temperature of 160F, or must it REMAIN at 160 for 1 hour? We purchase half-baked take-out pizza but heat it in our own oven to a confirmed 160F core temp throughout the pie. Even at that, it's overdone. If I leave it in for an hour, the birds won't eat it....
Similarly, I'm concerned about (lean cuts of) pork given all the outbreaks at packing plants. But pork has to come to 160F, and should be safe, Do you agree?   April 26, 2020
To clarify, there is no known coronavirus risk from food itself. There is likely little to no risk from the packaging, although to be extra cautious, you can heat in an oven, as described, to disinfect packaging. Since the virus does not last that long on cardboard (less than one day at room temperature), it would seem likely that heating the pizza box at 160F for even 15-20 minutes would disinfect it, although we are only speculating as we are not aware of an experiment that has attempted this. Of course, you could also just discard the box, put the pizza in or on something else, and wash your hands.

Anthony19711   April 27, 2020
I'm concerned that the pizza preparers might not always wear masks or gloves or practice good hygiene, so my questions were more specifici: Is BRINGING the temperature to 165 of, say, pizza (without the box) or a pork tenderloin sufficient, or must these STAY at these temperatures for some period of time to be certain kill all these coronavarmints...Thanks! (I'm not aware of any data on this, but given the outbreaks in meat processing plants AND that the these meats are always chilled or even frozen, it would seem a valid question. Many thanks.   April 28, 2020
As all studies with heat have shown that disinfection is function of both heat and time, it would seem best to maintain the food at that temperature for some period. Hard to say how long, but 30 minutes would seem reasonable. Again, there is no known issue with getting COVID-19 from food.

Leslie19694   April 26, 2020
Are glossy magazine and flyers that come in the mail considered to be akin to other paper in terms of virus longevity? Reason would seem to indicate that since they are less porous, the virus might live longer than on a standard envelope or cardboard box. What about the clear plastic view windows on envelopes? Are they more susceptible to lingering viruses than the rest of the envelope?   April 30, 2020
First, please note that the chance of developing COVID-19 from contact with mail items is likely to be extremely small, and you can certainly open and discard envelopes and then wash your hands. However, per your question, SARS-CoV-2 is likely so survive longer on the plastic window of envelopes than on regular paper. Based on the study of SARS-CoV-2 on paper in the answer above, and another study on plastic (see the virus survives much longer on plastic than paper (3 days vs. 3 hours). It's possible that it survives longer on glossy vs regular paper, but we are not aware of studies comparing the two. If you remain concerned, mail can also be disinfected by placing it in a warm oven, as described above.

Chris20090   May 31, 2020
What we do with our mail is to place it on an ironing pad and squirt steam from an iron onto the mail at close distance. This will melt the plastic envelope window
immediately. We then iron the paper envelopes front and back to disinfect it.

Gary20283   July 2, 2020
I'm not clear after reading this whole thread, how long I need to heat mail in an oven at what temperature. I'd like to do it at a higher temperature, say 200 degrees F., for less time as opposed to 160 degrees F. for an hour. Pre-heating the oven of course to ensure the temperature is actually at the indicated temperature.

Thanks for all the great information.   July 7, 2020
First, you don't have to worry about mail if you open letters, discard the envelopes, and then wash your hands before touching other things (including, most importantly, your face). The virus does not last very long on paper (only about 3 hours at room temperature), so even leaving your mail for a day (as long as not in the cold) should also greatly reduce any risk. We don't know an exact time at which an oven at 200 F would disinfect mail, but it would likely be short -- perhaps 15-20 minutes. But, again, this is not necessary.

Richard19687   April 24, 2020
Disinfectants have not been available in stores or online for weeks. Soap can kill the virus but it is possible to use undiluted dish detergent (straight from the bottle) on hard surfaces to do that? This may be the only alternative at this time. Also, can thymol-based disinfectants (such as Seventh Generation) kill the virus as effectively as Clorox-based and Lysol products?   April 29, 2020
The EPA's list of disinfectants for SARS-CoV-2 (linked to in the answer above) includes several thymol-based products. For most of these, the recommend contact time (the amount of time you allow the product to "sit" on a surface") are longer than what is recommended for bleach-containing products, so be sure to follow the directions for use on the label or as noted on the EPA's list.

Marsha19678   April 23, 2020
there are different types of bleach, eg laundry additives and scented ones.For disinfecting,must it be 100% sodium hypochlorite (and then diluted?)   April 29, 2020
The CDC advises that "diluted household bleach solutions (at least 1000ppm sodium hypochlorite)" can be used for disinfection. Please see their instructions at

Marsha19673   April 23, 2020
I read that , chlorhexidine and benzalkonium chloride were not as effective in killing COVID. . But in the article above , it states that it is . Can you clarify ? also I doubt anyone waits 15 minutes t..o let hand soap work on a surface, and hands only take 20 seconds to wash,so can you clarify that as well?   April 23, 2020
Because SARS-CoV-2 is a new virus, new or different information may become available as more research is done.

A review of laboratory studies found 0.05 - 0.2% benzalkonium chloride or 0.02% chlorhexidine digluconate to be less effective on coronaviruses such as MERS coronavirus and SARS-CoV than disinfectants such as 62 - 71% ethanol or 0.1% sodium hypochlorite (the main ingredient in bleach), but these studies did not test these disinfectants on SARS-CoV-2, the virus that causes COVID-19 (Kampf, J Hosp Infect 2020 -- -- also linked to in the answer above).

However, as noted in the answer above, a more recently published study by researchers in Hong Kong who studied the effects of various disinfectants specifically on SARS-CoV-2 found benzalkonium chloride and 0.05% chlorhexidine to be effective. The same researchers findings about hand soap solution can't really be compared to hand washing, where the goal is to remove virus (as well as inactivate any remaining virus) from the hands with rubbing, warm water, and soap.

Lilian19669   April 23, 2020
Thank you you so much for your very helpful information. Would steam cleaning surgical face masks for 10 minutes or longer using a double-boiler or something similar on your stove be a useful option too?   April 29, 2020
Microwave steaming of certain masks under controlled conditions has been reported by the CDC (see but there does not appear to be information on other steaming methods.

MaryLee19651   April 22, 2020
My first question is: Before I place items in the refrigerator or freezer, I wipe them down with a disinfecting wipe or alcohol, and was wondering...How long should I wait before placing them in the refrigerator or freezer? Do they have to be dry before putting them away in order for the virus to be dead?

My second question is: Sometimes I place things in a small paper lunch bag after they have been wiped down, and then I place them (in the bag) in the refrigerator or freezer...My rationale for doing this is just in cast the virus isn't dead yet, at least the container won't contaminate other stuff that it sits next to on the shelf. Please advise as to whether or not this is a good approach to staying safe, or is it going overboard. Thanks!   April 23, 2020
Yes, it would probably be best to allow the packaging to sit for the necessary amount of time as noted on disinfectant's label or the EPA's list (linked to above). If you've done this, it is not necessary to place the products in bags or separate them from other products.

jan 19672   April 23, 2020
So if it is recommended that bleach is effective after sitting for 5 minutes and soap after 15 minutes, frozen and refrigerated packages would have to sit out at room temp for that long. But the frozen will partially defrost. Correct?   April 23, 2020
Please see the USDA's information about freezing, thawing and re-freezing for safety guidelines:

MaryLee19650   April 22, 2020
I have some lysol disinfecting wipes that are at least 2 years old (maybe even older than that). I don't see any expiration date on them. .Are they still effective at killing the virus as long as they are still wet?   April 23, 2020
We don't have information about that, but a Lysol representative posting on the company's Facebook page ( has stated "Our products do not carry an expiration date. The product has a shelf life of two years from date of manufacture." We will reach out to Lysol and update this post if we receive more information.

MaryLee19688   April 25, 2020
Thank you!

Frances20010   May 24, 2020
I have a number of containers of Food Lion brand disinfecting wipes, which I've always considered to be Clorox wipes. There is no discernible (to a consumer) expiration date.
Since Clorox claims their wipes have an expiration date of one year, should I consider that these no longer work, since most of them are over one year old? It's impossible to replace them in my area.   May 28, 2020
Since the shelf life of wipes can vary by brand and ingredients, it would be best to contact Food Lion to find out where the date of manufacture is printed on the product and/or information about the product's expected shelf life.

Lucia19649   April 22, 2020
Hi, thank. you for all of the information you are providing here. It is extremely helpful.

I am making my own cloth masks and have left a pocket to include a filter. After watching a video by Texas A&M on making a homemade mask, I have ordered AIRx HEALTH 20x20x1 MERV 13 Pleated Air Filter to use as a filter in the mask. It is represented to be fiberglass free in the online description.

Do you have any information about the safety of using these kinds of filters in masks?   April 29, 2020
No, we don't have any information on the safety or efficacy of using this type of mask.

Cynthia19641   April 22, 2020
Can a mask be disinfected by putting it in a paper bag and then microwaving for 10-15 seconds?   April 29, 2020
N95 masks should not be placed in the microwave. The CDC has reported some successful disinfecting of certain masks by placing in them in microwave steam bags, but this would be difficult to duplicate due to differences in construction and power among microwaves, and differences in masks. You can find more information about that here

Steven19638   April 22, 2020
I take my mask off by the straps and hang it up for 7 days until I need to go to the store again. I don't see why this wouldn't be adequate since I'm not touching the mask itself   April 22, 2020
Hi Steven - That should work well, as long as the mask is kept at room temperature or above.

Catherine19666   April 23, 2020
I leave mine in the car and since I only go to the grocery store once per week, I am sure this will suffice. Plus, I live in South Florida and it gets pretty hot in that car for hours and hours at a time during the day!

Elizabeth19635   April 22, 2020
So, we have the option of risking the virus by refrigerating those products that require it or food poisoning by letting them sit out at room temperature? Since we're also told not to wipe food products down with disinfectants, for obvious reasons. They should change the name from COVID-19 to CATCH-22.

Trinston19663   April 23, 2020
Agreed. I use citrus wash to clean my vegetables in a very very clean sink. Also, I only buy enough perishables for a week. It's about time to grow our own vegetables good people. Seriously, 40lb or more of potatoes grown in 30-55 drum can save a life and it's much cheaper. We're living in a different world.

Deborah19674   April 23, 2020
I would love to know how you grew the potatoes!!!

Karen19664   April 23, 2020
Wouldn't those foods generally have some packaging, with the exception of fresh produce? It seems that it would work to wipe down the packaging with whatever is best before putting it in the refrigerator or freezer.

Produce would have to be washed, but that's always a good idea.

Gary19627   April 22, 2020
I have a ozone generator, 10000mg per hour. I plan to use for virus decontamination, food, cloths, mail etc.   April 22, 2020
Hi Gary - Please be aware that the EPA advises against using ozone generators in occupied spaces. See

Ellen19878   May 12, 2020
I think the operative word in the EPA's warning is "occupied." Ozone will kill people and pets as effectively as it kills virus and bacteria, although it will take longer. Therefore, the area being saturated with ozone should be free of anything you want to live.The advantage ozone has over UV-C is that the pathogen does not need to be in the direct line-of-sight to the sterilizer, as it does with UV-C light.

DAVID19785   May 3, 2020
I have one as well, use it in a sealed container. I plan to use it on my N95 mask. Will that be effective? Any issues with mask integrity?   May 4, 2020
We are not aware of any tests of ozone generators on mask integrity. Please see our response above.

Pavel19949   May 20, 2020
I have 5000mg/h machine and use it in a big enclosed plastic container 6x3x2ft outside the house. Anything from outside goes into the box for 10 min treatment before going into the house. Food, close, mail... I've read on abstracts that this kind of exposure should be enough to destroy nearly any form of life.

*Could you please confirm if you came across any such studies? *

Only disadvantage I see so far is that O3 exposure destroy plastics and rubber with repeated exposure. Rubber gloves will not survive (and should not), plastic bags become sticky to touch and loose integrity, metals will rust rapidly if moist, etc.   May 20, 2020
We don't have information on your particular machine, but please see the information about ozone generators here

Stan19623   April 22, 2020
I am wondering if the latex rubber straps on many masks, as well as latex gloves, are not also causing allergic reactions in people nowadays.

Robert19619   April 22, 2020
If the providone-iodine, chloroxylenol, and chlorhexine were so effective, why do they not show up on the EPA's "List N"?

Repeated searches for these disinfectants yielded a "No Matching Records Found" result.   April 22, 2020
Hi Robert - That study was published just weeks ago, so it's still very new. On it's website, the EPA notes: "Additional disinfectants may meet the criteria for use against SARS-CoV-2."

It's also possible that some products containing these ingredients have not registered with the EPA or list human coronaviruses as a target pathogen on the label. See the EPA's answer to the question "I want to use a product to kill SARS-CoV-2 but it isn't on List N. Is it effective against SARS-CoV-2?" (

james19597   April 21, 2020
If the purpose of a mask is to protect others, why clean it? If it is contaminated, that means that the owner already has the virus?
If an external contamination happened, then would not the cleaning. and handling cautions apply to all clothing and all exposed body parts?

Edmund19615   April 22, 2020
If a person were not infected, I would speculate that the increased touching of one's face (by putting an unfitted/home made mask on, adjusting it and taking it off) may actually raise the risk of coming in contact with the virus. I have found no evidence that these home made masks are effective at all in preventing transmission. If there is evidence, I would appreciate it if someone would point me to it. Thank you.   April 22, 2020
Hi Edmund - An article in JAMA notes the following: "Primary benefits of wearing a mask include limiting the spread of the virus from someone who knows or does not know they have an infection to others. Masks also remind others to continue practicing physical distancing. However, nonmedical masks may not be effective in preventing infection for the person wearing them." The article is found at

Susan19620   April 22, 2020
It does seem the advice is contradictory. The podcast, Coronavirus Morning Report today talked about the virus on clothing and doesn't seem to be a big problem. They suggest if someone sneezes directly on you it might be prudent to change. They said all clothing can be washed together even if someone is ill. I would guess the same would hold true of a cloth mask? I figure any protection is better than none. I really like this podcast. It deals with science and always gives the source of any information it presents.

Stan19624   April 22, 2020
My take on this is that we should not go overboard. Prudent precautions yes, but also reasonable ones. Unless we work in a hospital or are in contact with a lot of people there should be no need to wash our clothing or shower every time we come home from the outdoors.The CONCENTRATION of virus contamination is what counts. If we properly. maintain distance, wash our hands and sanitize our environment wisely, we will get through this. What I do is wash my hands before puttting on a mask. Then I wash them again BEFORE I take off the mask, then wash them AGAIN after the handling the mask and disinfectng it. It's a bit of a hassle, but that's what we need to do nowadays to stay safer.
However with regard to clothing, according to a recent CDC bulletin there might be an issue with tracking in some level of the virus on our shoes. I would think that pets might be somewhat susceptible is that were the case (and assumIng that they are at risk??). So when I come in from outside I disinfect the soles of my shoe, put them aside,and then wear clean slippers in the home. In fact I have another pair of slippers outside my door to use for picking up the mail, taking out the trash, etc. Even when there is no virus to worry about, why track in dirt from the outdoors when there are simple solutions to remedy that?

Robert19629   April 22, 2020
I am a researcher and have good friends at CDC. The guidance that masks are for the protection of others is driven by statistics and not whether a mask will protect you, which it will. If you are infected, you stand to infect many others whereas if you protect yourself, your consumption of a mask protects only one person (excluding transmission to others in both cases). CDC guidance is often based on general policy of thinking the public will panic. I disagree with this policy and think the public should be told the full truth at each stage. As for masks, almost any mask will protect both you and others to some extent. Unfortunately, kerchiefs and scarves add protection at a typical level of 5-10% whereas denim and a handful of other materials can protect into the 70% range. Multiple layers are generally better because of the statistical probability that spaces will be offset to create smaller passage. Keep in mind that we have little absolutely reliable data on how the virus can propagate, how long it can live on surfaces, etc. What we do have is hurried studies the findings of which will almost certainly change at least a little over time. Following all of the guidelines 100% is the best advice we have at the moment. Even if it turns out that some of the guidance was not necessary, we don't know which is which right now..   April 23, 2020
Yes, cloth and surgical masks are meant to protect others. N95 masks (more correctly called respirators) protect the user (and others). If you are the only one who wears the mask, disinfection is only necessary if you are concerned that the mask has been contaminated from an external source.

Juliana19686   April 24, 2020
I have heard that the more virus and the more you are exposed to the virus, the higher chance you will be taken down by the virus instead of fighting it off. I would not want to re-expose myself to more virus by using an infected mask.

Tina19596   April 21, 2020
Could you tell me if putting paper bags and my jackets in the garage for 3 days will dissipate any viral particles they might have. I put the bags and my jackets in the garage so that I don't have to spray or wash them when I come back from the store.

Tod19600   April 21, 2020
If your garage is at least room temperature, that should work fine and, for paper, you don't need to leave it for more than a day.

Lynn19579   April 20, 2020
I just wanted to thank you and your team at for the work you have done on this issue, as well as your research in other areas. I find it extremely valuable. Subscribing to you has turned out to be a very good decision. Thank you again.   April 20, 2020
Thank you for your kind words Lynn. We are glad you are enjoying

larry19628   April 22, 2020
Thanks for another good article. I've also been looking at this topic and just ran across this article by you folks. Sanitizing materials have been difficult to get where I live, so I've been looking at alternatives. One is the use of hypochlorous acid (HOCL) which I can make myself using a EcoloxTech appliance. HOCL seems to be a very effective sanitizer which is less hazardous than most others. It even seems to be safe for sterilizing fruits and vegetables that may have rather contaminated surfaces from being handled by multiple people at the supermarket. I'd like your opinion on that use since most other sterilizing materials cannot be used on food. Also, it does not necessarily need to be rinsed off because of its low toxicity, thus somewhat simplifying its use.

I've also used a home oven to sterilize masks, BUT my oven temperature dial is more than 50° off at low (oven) temperatures!! Since the temperature is quite critical, it is necessary to use a precision thermometer for this usage. Even a high quality "meat" thermometer was 3-4 degrees off, which is enough to make a significant difference in being able to sterilize masks.   May 5, 2020
The EPA includes hypochlorous acid on its list of disinfectants for use against SARS-CoV-2, although it requires a longer contact time (10 minutes) than some other disinfectants. Be aware that when used in washing fruits and vegetables, this should be followed by rinsing to remove residues (

Jack19957   May 20, 2020
Actually, the guidance referenced indicates either rinsing or waiting 10 minutes. Hypochlorous acid is very safe compared to other disinfectants. It has been studied extensively for multiple uses and effectiveness. It is widely used fas a food disinfectant, wound cleanser, eyelid scrub, etc. Yes, other disinfectants have shorter dwell times, but are nowhere nearly as safe. The most widely recommended disinfectant, Bleach, is quite dangerous, has a shelf life, and most literature suggests a 10 minute dwell time. There is a wealth of information on hypochlorous acid from reputable sources. Numerous studies of different uses have been published by the NIH. I have no financial interest in the sale or manufacturing of products containing of generating hypochlorous acid.   May 20, 2020
You are correct; the FDA states: "When used in water to process fruits, vegetables, ready-to-eat meats, and fish and seafood products intended to be consumed raw, the treatment will be followed by either a 10 minute drain step or a potable water rinse to remove, to the extent possible, residues of the ... [food contact substance]." (

The EPA's instructions ( for hypochlorus acid on non-porous surfaces varies from 5 to 10 minutes contact time and states "Food contact post-rinse required."

john19621   April 22, 2020
I second the compliment for u all's help now, but also since ive been a member (for approximately 5 years)   April 22, 2020
Thank you John. We're glad to hear you are finding ConsumerLab helpful.

Luis19626   April 22, 2020
Lynn is right, you guys are the bees kness!

monica19566   April 20, 2020
Can I put the N95 mask on the dryer with a wet cloth?

Steven l19595   April 21, 2020
how about O3 or ozone treatments? using CPAP sanitation?   April 22, 2020
Hi Steven - We've added information about CPAP and other ozone devices here

Nancy20199   June 17, 2020
OSHA has tested gaseous ozone and shows little to no problem until extended lengths of time at high levels for workers in municipal water plants. I do not think an ozone generator for a room could possibly reach that high a level, but then I do not have a ozone gas generator.   April 22, 2020
If you mean putting an N95 mask in a clothes dryer with a wet cloth, that would seem inadvisable as 1) the mask could get wet -- which you never want to do with N95 masks and 2) a rotating dryer could alter the shape/fit of the mask.

Wesley P.19564   April 19, 2020
If Lysol is sprayed on both sides of a standard surgical mask or any mask for that matter and allowed to dry (in a car for instance) will that kill the COVD19 virus? Wesley46

Tod19575   April 20, 2020
It may kill the virus but compromise the mask. Don't wet surgical or N95 masks.

Deborah19560   April 19, 2020
Thank you very much.

Ken19555   April 19, 2020
Hi. Thank you very much for this article. Can you please address the following questions/topics?

1. This doesn't quite make sense to me - the HK research shows that "five minutes at only 158F (70C)" was sufficient to destroy the virus. Why then, would we need 60 minutes at 150F (65C) for a take-out food container? It's only a few degrees lower. Even at a temperature of 132F (56C) the research says it only needed 30 minutes.

2. How do we disinfect refrigerated containers and frozen goods packages? Things like frozen vegetables come in thin, plastic packages that are often not sealed well.

I contacted Clorox and asked if it was safe to use their disinfectant wipes on food containers (and specifically frozen vegetable packaging) and they said "no". Can you clarify / expand on this? What do you recommend?

3. Would simply wiping a container with a wet cloth/paper tower reduce the amount of viable virus on the surface?   May 6, 2020
That experiment was not with a food container, but with cell culture. Best on the side of caution and allow plenty of time to heat, as noted in the answer.

We've reached out to Clorox for more information. Please note the FDA's statement about food packaging and the risk of transmission of coronavirus at the beginning of this answer.

Alan19543   April 19, 2020
In the article they mention that coronavirus does not last on food but will stay on packaging that may be refrigerated or frozen. Would the solution for that to be wash your hands after right after touching the packaging? That seems more practical than leaving the package sit at room temperature out or rub hand sanitizer on the package.

ROBERT19618   April 22, 2020
Then you end up with the virus in your fridge/freezer.

Dina19537   April 19, 2020
"Fifteen minutes were required for the virus to be undetectable when exposed to a hand soap solution".
Is "exposure" to hand soap different that the 20 second hand washing we're all doing? Why so long?   April 21, 2020
Hi Dina - You really can't compare that result to hand washing, where the goal is to remove virus (as well as inactivate any remaining virus) from the hands with rubbing, warm water, and soap.

Dina19606   April 21, 2020
Got it, thanks.

MICHAEL19536   April 19, 2020
Conflicting/confusing information abounds.General concensus in the media is the virus lives 3 days on plastic and stainless steel(no mention of non-stainless steel like the kind canned foods come in...assume it is shorter)? it says the virus is still detectable on these surfaces at day 7 (but at 0.1% of original level)...Haven't seen any mention anywhere about viral load relevance to developing the disease.

AARON19532   April 19, 2020
You say, "[R]ecent tests with SARS-CoV-2 in Hong Kong showed that it became undetectable after just five minutes at only 158F (70C)." So, if we pre-heat the oven (and even more so if our ovens only go down to 170 degrees), why do we need to keep it in there for an hour?   April 21, 2020
Hi Aaron - As noted in the answer, that experiment was not with a mask, but with cell culture. A study that used an infected N95 mask found that 50 minutes was required at 158F (70C) for the virus to become undetectable. Better to use that study, and err on the side of caution. We mention the cell culture study to point out that less heat and time was needed to inactivate the new virus than another SARS-CoV virus (not the one that causes COVID-19) that was similarly tested in cell culture, showing that the newer virus is more heat sensitive.

AARON19603   April 21, 2020
Thanks. To be clear, I'm concerned about takeout/delivery containers/food (not masks) - and just wondering if we still really need to keep it in there for an hour (at 170 degrees, since that's as low as I go).

Barry19530   April 19, 2020
I wear a mask for approximately a half hour, once or twice a day. Here's my "plan". I have 10 masks. I've numbered them 1-10. I wear #1 and then put it on the bottom of the pile. By the time I get back around to wearing it, it has been several days (often 10 days). Do you think this would kill any virus on mask #1?   April 20, 2020
Hi Barry - As long as you are keeping the masks at room temperature and not in a cold area, that would be a good approach with regard to coronavirus, as it will not last that many days. Of course, other microbes (e.g., fungal spores) could persist but if the masks are clean and dry, this is probably not significant issue.

Barry19676   April 23, 2020
Thanks so much for you answer.

Charlyn19517   April 16, 2020
Will microwaving food kill.the virus? Charlyn   April 16, 2020
Food itself has not been shown to be a mode of transmission for this virus, so no need to microwave the food with regard to virus.

Susan19511   April 15, 2020
I don't understand that the covid-19 virus is not viable after 2 days at 98.6 degrees F. Would that not mean that the virus was killed when a person had a fever for a few days? Can someone explain that? Thank you.   April 15, 2020
What you need to remember is that while viral particles become inactivated over time, many more are being made in infected cells. The infection continues until one's immune system is able to stop it.

Joseph19498   April 15, 2020
Certain masks have elastic or rubber straps to ensure a tight seal. Others (e.g. P95) have plastic squares in the center.

Would baking, even at those temperatures destroy the elasticity of rubber / elastic and potentially melt plastic?   April 15, 2020
Let's back up: You should not be baking masks. Baking temperatures (typically above 325F) are much higher than the 150-170F that are being suggested. These lower temperatures have been shown to be safe for masks.

Joseph19508   April 15, 2020
Incorrect logic leap!

In no fashion was the term "baking" meant to imply anything other placing an object in an oven, or toaster oven, with the oven setting as "bake" (at least that's what my oven calls it, as opposed to say "broil") with a temperature setting aligned with guidance here (150-175 degrees Fahrenheit). I do not know of any other way to accomplish this?

From Consumerlab's response, the presumption then is that the elastic / rubber bands that fix the mask to the wearers face will not become brittle or otherwise elasticity compromised at these temperatures.   April 15, 2020
We just wanted to clarify, in case others misread your post to assume that baking temperatures were being suggested. As discussed in our answer, this has been tested (at 85% humidity) on N95 masks without loss of function or fit for 20 cycles. Will they eventually give out? Most likely. Remember that these are intended to be single-use, but warming the masks as described appears to be a viable option for extending their useful life.

Joseph19510   April 15, 2020

Barbara 19494   April 15, 2020
Thank you so much for this article. For me it is a wake up call to be more purdent on my efforts to disinfect. It is a great summary of effective methods of disinfecting against COVID-19, but also a reality check on the actual time of exposure to heat and disinfectants required to be safe. A swift pass with a disinfecting wipe - may help, but will not render the item free of the virus! Thanks!

Deborah19492   April 15, 2020
It seems like ironing a cloth mask with a steam iron would easily work to kill the virus. I wouldn't do it to an N95, however.

B19483   April 14, 2020
I appreciate your info on the viability times of the corona virus on groceries and packages, which I am very concerned about. However I feel I cannot use what you have given us as it appears to contradict other tests.This would be a horrible mistake for me to make. I remember the CDC? tested infected rooms in cruise ships and found traces of the virus on hard surfaces SEVENTEEN days after they were inhabited. I have not been able to locate data on the specific tests so I have no idea if the virus was still alive and able to infect. Could you please clear this up ? Thanks fo all you do for us on so many levels.   April 14, 2020
The report you are referring to regarding a cruise ship was later updated to clarify that genetic traces of the virus were found, not infectious virus particles.

Ernest 19474   April 13, 2020
Will a spray of hydrogen peroxide on a mask followed by a drying cycle in a cloths dryer be sufficient enough to kill the coved-19 virus?   April 15, 2020
As noted in the answer above, it is not advisable to spray liquids on N95 masks. If you are referring to a cloth mask, spraying is probably not necessary if you will be putting it through a drying cycle in a cloths dryers -- although it would be better to just wash it in a washing cycle and then dry it.

narcis19473   April 13, 2020
Can Isopropyl alcohol be used to disinfect (food, surfaces, hands) and at what concentration should it be used?   April 13, 2020
Hi Narcis - Yes, isopropyl alcohol (70%) can be used to disinfect surfaces and is a common disinfecting ingredient in hand sanitizer (see; It should not be used in foods.

Ernest 19472   April 13, 2020
You mention using disinfectants. Will spraying a pre formed fitting masks with hydrogen peroxide work? I took a P95 mask and inserted it with a MERV 13 (virus intercepting) filter that I cut from a new furnace filter.

Nancy19448   April 12, 2020
Thank you for this article. It confirms that what my husband and I are doing is good. Thank you.

Jodi19447   April 12, 2020
I have put isopropyl alcohol in an atomizer and I spray the outside of my mask with it. Is that effective?   April 15, 2020
As noted above, it is not advisable to spray N95 masks. If a cloth mask, washing in a clothing washing cycle is recommended.

Dorene19445   April 12, 2020
I would not recommend any heating of takeout containers due to their own chemical constituents leaching into the food. You really never want to heat anything in plastic or Styrofoam and beyond that many fast food wrappers and containers are treated with chemicals that keep foods from sticking to them that are known endocrine disrupting chemicals. Far better I think to put the food on your own plates (or in your own storage containers) and toss the takeout ones. Wash your hands and be careful not to cross-contaminate.

Lauren19442   April 12, 2020
Where is the reference for the viability of coronavirus on surgical masks?   April 13, 2020
Hi Lauren - The reference is (Chin, Lancet 2020 -- as noted in the answer above.

Georgia 19441   April 12, 2020
Does the ultra violet light devises work to kill it & do you know how to pick out a good one.   April 20, 2020
Hi Georgia - UV light in the C range can kill coronavirus but, for home use, is not that practical, as explained in our answer to this question (which includes reviews of products) at

Bernie19438   April 12, 2020
I put my N-95 mask in the dishwasher. I got it last summer and used it when I mowed the lawn for my

Bernie19514   April 15, 2020
I did not get to finish my comment here as I accidentally hit the submit button. The mask was quite soiled when I placed it in the dishwasher and it came out looking brand new. Is it still functional? I just had it on regular cycle not sanitize   April 16, 2020
It may be cleaner but it there is a good chance that it is not as functional as before. Anything that wets an N95 mask may reduce its functionality.

DAVID19436   April 12, 2020
I use a Respify ozone generator to disinfect my CPAP equipment. Would it be effective for disinfecting masks?

Lynn19558   April 19, 2020
I would be interested in a reply to the ozone question too. I was going to ask that very question and then saw it had already been asked here.   April 22, 2020
Hi Lynn - We've added information about ozone devices here

Lynn19662   April 22, 2020
I should have asked with more detail. My husband has a portable ozone machine for his CPAP that he uses in a large (12 quart) plastic container, with a lid.

I wondered if the mask (N95) can be put in there to sanitize? Of course, he leaves his CPAP in the container after the ozone machine is done, usually for about 8 - 9 hours. Then (for the CPAP machine) he runs it for a couple minutes to "clear it out". But my actual concern is the N95 masks if it is run in the container like the CPAP..   April 23, 2020
Hi Lynn - Unfortunately we haven't found any information specifically about using CPAP ozone sanitizers for N95 masks, but as noted here the FDA has expressed concern with these machines even for cleaning CPAPS.

Wynne19435   April 12, 2020
Is it ok to spray a mask with a disinfectant and then continue to wear it at a later time?   April 15, 2020
Not for an N95 mask, as noted above. For a cloth mask, it is recommended that it be washed in clothing washing cycle.

ann19422   April 12, 2020
I've been using a paper towel saturated with 70% alcohol to wipe off containers from the grocery store. Is this sufficient?

Carey19421   April 12, 2020
What is meant by at a concentration of 1:49 or 1:99? What part is water and what part is the bleach?   April 20, 2020
Hi Carey - The smaller number would be the bleach. The CDC recommends 4 teaspoons bleach per quart of water:

Janice19412   April 12, 2020
Place a raised rack on the floor or a counter to put food on, which has just been disinfected, for the time needed for total disinfection. That way the bottoms of the containers are not compromised.

AARON19406   April 12, 2020
As others have stated, my oven only goes down to 170 degrees. If 150 degrees works for 5 minutes, how long would I have to put takeout/delivery bags/packages/containers in the oven for at 170 degrees? And are plastic/paper takeout/delivery containers stable at 170 degrees for that period of time?

Katherine19631   April 22, 2020
Please read Dorene's excellent comment above about take-out and any other paper ( they are paper plus...other chemicals usually)

Arch20131   June 5, 2020
According to chemical reaction theory that would represent about 2 minutes.

Karen19405   April 12, 2020
I read on CDC that spraying N95 mask with 3-6% hydrogen peroxide will work to make the mask re-usable and can be re-sprayed many times. Let it dry completely before using. I hope this is correct info. I also saw steam noted.   April 23, 2020
As noted above, it is not advisable to spray N95 masks. The CDC does report on some research in which N95 masks were submerged in liquid hydrogen peroxide and this was shown not to effect filtration, but the researchers did not test how well this procedure worked for disinfection, or whether it altered the fit of the mask (see

Gail19403   April 12, 2020
What do you know about ozone killing viruses?   April 22, 2020
Hi Gail - Please see the information about ozone that we've added here

beverly19396   April 10, 2020
I buy fresh muffins, bagels, cookies etc from the bakery section at the store. When I get home I place them on a cookie sheet and heat them in the oven at 300 degrees for about 20 minutes. If anything these items might get a little crust on them - (makes them more tasty imho ; ) and then I let them sit until they cool.

Jaclyn19387   April 9, 2020
I have an N95 mask, but my oven doesn't turn on below 170 degrees. I'm hoping 170 for 15-20 minutes will work without destroying it.   April 9, 2020
We can't advise this, but that will probably be fine. Best to keep it away from any heating element and keep an eye on it, also probably best to place it on a cooking sheet. If you try it, please let us know how it goes.

aaron19395   April 10, 2020
I have the same issue with my oven but I've used it just fine for sterilizing n95 masks. I use a stick of wood to suspend the mask inside the oven so no part of it touches the inside of the oven. The wood sick may get a little brown but no where near combusting.

Jaclyn19569   April 20, 2020
I've put my N95 mask on a cookie sheet in the middle of a 170 degree oven and away from the heating unit, with a pan of water next to it, and noticed that the printing on the front of it is disintegrating. Any indication as to whether this means the mask is losing its integrity at a faster rate?   April 21, 2020
You might want to be sure that it's not just uneven printing on the mask material. If you are able to try this again with another mask, take a photo of the label before and after. By the way, it is fine to lower the temperature (if you can) to 158 degrees Fahrenheit and limit the time to 50 minutes, or, if your oven won't go below 170 F, decrease the time to 30 minutes. If you try this, please let us know your results.

Jaclyn19610   April 21, 2020
When I first purchased the mask the printing was quite legible and easy to read; after one trip to the oven, now the verbiage is blurry and indistinguishable. I meant to indicate in my last post that I heat the mask for no more than 30 minutes.   April 21, 2020
Thank you for letting us know. We have tested it here on N95 masks at both 150F and 170F (along with water in a pan), each for 1 hour, and did not observe a change in text on the fabric, although at the higher temperature, the mask became slightly more stiff. Should you attempt this again, please photograph before and after and email us images at

Mary19443   April 12, 2020
I have a couple of N95 masks that I spritz with 95% alcohol after I wear it, and then I let them sit for at least 24 hours before wearing the again.

leona19482   April 13, 2020
I would also like to know if spritzing with alcohol works great question.

Diana19476   April 13, 2020
I put my masks on a cookie sheet at 170F for 30 minutes (with a pan of water in the bottom of the oven). It's been fine,

Katherine19632   April 22, 2020
I missed the pan of water addition to the oven that CL also noted... where to find the reason for the pan of water. Obviously, it is to moderate the potential for too much heat compromising the mask's fiberous material , correct ?   April 22, 2020
Hi Katherine - Yes, as noted above, the humidity may help protect the integrity of the mask.

Jimmy19383   April 9, 2020
Just wanted to add this recent study in the Lancet Microbe journal testing SARS-Cov-2 on different surfaces and temperatures and with different disinfectants:

results table:

The good news is that SARS-Cov-2 appears to be more heat sensitive than the first SARS coronavirus. At 56C (132F) the virus is undetectable after 30 mins and at 70C (158F) it's gone after 1 min.

The bad news is that it can last a while on a certain surfaces at room temp, 7 days on the outer surfaces of masks, 4 days on stainless steel and plastic.

Alexander19376   April 8, 2020
I looked at the WHO Myth Busters page you referred to.

I am surprised they mention UV light but NOT UV-C light which is shown to kill 99.9% of viruses.

Further more. they do not mention ionizers (negative ion generators) nor ozone generators.

All the above are proficient in killing viruses (as well as other pathogens). Please comment   April 22, 2020
Hi Alexander - Please see our CL Answer about UVC light and coronavirus, which includes information about ozone devices

Heather19356   April 8, 2020
Disinfectant is scarce. I wash every container that comes into the house with soap and water for 20 seconds. If it works for hands it will work for containers.

Mary19429   April 12, 2020
I wash vegetables and fruits by soaking them about 10 minutes or so in Braggs Apple Cider Vinegar. Then refrigerate.

Alexander19334   April 8, 2020
Will freezing the virus kill it?

Patricia E19375   April 8, 2020
Absolutely not. It helps it live longer.

Lida19401   April 12, 2020
Your advice not to place containers immediately into the refrigerator or freezer leaves me wondering what to do with food that is purchased and that needs to be refrigerated

Sandy19553   April 19, 2020
Disinfect the containers with alcohol, bleach solution, wipes or soap & water and let them air-dry. That short time lag will not cause the food to spoil before you chill it.

Tod19574   April 20, 2020
Just clean them first by applying a disinfectant.

karen19320   April 8, 2020
I'm wondering if microwaving a cloth face mask will kill the virus and if so, how long would I microwave for?

Sue19337   April 8, 2020
Don't put cloth in the microwave! Do you have a clothes dryer? You can run the cloth mask on high heat. Cloth will scorch in a microwave.   April 8, 2020
The temperature in clothes dryers at high setting is apparently around 135 degrees Fahrenheit, so it's possible it could work. But best to just wash cloth masks in a washing machine with warm or hot water, as that should disinfect them.

M19407   April 12, 2020
Some dryers have a "steam" (or "steam sanitize") setting -- since moist heat is apparently better, I wonder if this would make the dryer more effective than the standard "high" setting?

James19455   April 12, 2020
The dryer idea seems less than ideal unless you want to aerosolize the virus.   April 14, 2020
Again, best to wash cloth masks in a washing machine. It can then be dried in a dryer.

Katherine19633   April 22, 2020
I thought that I read somewhere on this site that the rotating of the dryer might damage the mask... also, I have wondered about the advice to use the washing machine as well.Please elaborate as you, CL, keep repeating this advice.   April 22, 2020
Hi Katherine - As we've responded to other comments, you would not want to put an N95 mask in a washing machine, as this type of mask should never get wet, and a rotating dryer could alter the fit of the mask. For cloth masks, using the washing machine and dryer is advised.

Kim-Sandy19432   April 12, 2020
Damp cloth if a mostly natural fiber will not scorch. I microwave my dishtowels and dishrags.

Janet19439   April 12, 2020
Most face masks have a metal strip to allow you to fit the mask around the bridge of your nose, so microwaving them may not work out too well.

John19381   April 9, 2020
please use CAUTION with UV-C light,
The risks with UV-C are severe for your eyes, and skin. A truly disinfectant time of dose could leave you BLIND. Be very, very, very cautious with UVC in the range say 240 to 290 nano meter sources of light . Deadly to virus, but also very, very, bad for eyes and skin.
The supposed wands that show up in your feed? Maybe they work, maybe they don't. There's alot of "snake Oil" and fake devices.

Milla19392   April 9, 2020
UV-C is highly effective didinfectant. They are widely used in hospitals in other countries. People, of course, are asked to leave a room...
I have a very old "Sun lamp" and disinfect my mask when back from a supermarket.

kerry19500   April 15, 2020
The hospital I work at is doing a bleach disinfection of the room and no one can enter the room for a little over an hour. We aren't using those heat disninfectors at all for this--though we've used them regularly with other isolation diseases

Steve19478   April 13, 2020
I have a strong UV-C light that I use to kill mold in the shower stall (the stuff that grows under the caulking). I was planning on using it to disinfect my N-95 mask (I only have one that I found in the garage). I use a switch so I turn it off and on from outside the bathroom with the door closed so no eyes or skin are exposed.

kristine19547   April 19, 2020
Exactly. Consumers should NOT use UV-C devices at home. They are simply too dangerous, especially to eyes. As you mentioned, many of these "devices" sold may not emit the correct wavelengths of UV-C anyway, so they are useless. There is no way to validate claims printed on the device packaging without using professional-grade equipment in a lab.

Also note that wearing ordinary eyeglasses, contact lenses, and sunglasses WILL NOT PROTECT YOUR EYES because the UV-C intensity (assuming the device behaves as advertised) is MUCH TOO INTENSE for ordinary UV-blocking coatings on eyewear.

As a scientist who used UV regularly, I needed to wear a special, professional-grade face shield that I (or rather my lab) purchased from a reputable scientific equipment supplier.

L19735   April 29, 2020
There are UVC lamps that appear to be intended for consumer use, made with timers (to shut off after passage of a prescribed time) and delayed start (several seconds delay to allow the user to shut the door to the cabinet or room). I've used one for years to remove chloramine from municipal water, when using city water in ferments like kombucha or sourdough starter.

Philip19313   April 8, 2020
last week my wife and I made a large shopping buying frozen vegetables, eggs, frozen fruit, milk, etc. How long do we wait before putting them in the refrigerator?!   April 8, 2020
You should wipe them all down with a disinfectant and then you can refrigerate them. Refrigerating is not a problem if you've already disinfected the outside of the packaging.

gary19460   April 12, 2020
Can you please say what disinfectants work for wiping down items from grocery store? I cannot get hand sanitizer, disinfectant wiped or 70% alcohol anywhere, I was able to get 50% but thats it.   April 23, 2020
Please see the EPA's "List N" ( linked to in the answer above, for other disinfectants.

Gina19322   April 8, 2020
Just put 1 part bleach to 4 parts water in a spray bottle; saturate a paper towel or old cleaning cloth and wipe down your groceries and put them away. Wipe down your fridge handles, pantry knobs, purse handles, wallet, phone and keys and then of course, wash your hands.

Julie19357   April 8, 2020
Would love to find bleach! Not in stock anywhere!

Eric19369   April 8, 2020
Try swimming pool supply houses. See if they have pool chlorinating chemicals - i.e.,
bleach in plastic gallon jugs

Jerri19413   April 12, 2020
Take care in using pool chemical bleach. It is not the same as household bleach and is not meant to be used inside in confined areas. Can burn your lungs.

Barbara19685   April 24, 2020
Try looking for bleach in drugstores, hardware stores and even in AM/PMs. I've seen it in all those locations albeit only half gallons. But they will still work the same.

Deborah19420   April 12, 2020
We buy 10% chlorine at Ace Hardware for the swimming pool and dilute it for indoor use.

Judith19386   April 9, 2020
What about rubbing alcohol? My hands are weak & I'm apt to ruin all my clothes with splatters of bleach solution

Tina19410   April 12, 2020
According to CDC guidelines you only need 4 teaspoons bleach to one quart of water for a cleaning solution. I keep a jar of this solution on my counter and use it daily to disinfect and also to wipe down my groceries.

Kelly19324   April 8, 2020
We take an divide our counter top into a "dirty and clean" area, use tape if you like. Then all groceries from the store are placed in the dirty area. Each item is either then wiped with sanitizing wipes or sprayed and wiped with Lysol spray and placed in the clean area. In the case of fresh produce, we wash with soap and water before consuming but spray "exterior" and wipe before placing in refrigerator. After each item has been cleaned and moved to the clean area, hands are washed and then the items are put away.

Note, in some cases, simply removing outer packaging is sufficient such as with packaged cereals and other "no hands" produced items.

Linda19366   April 8, 2020
I use a variation of this technique. Instead of dividing countertop into clean and dirty, I place all containers (boxes and bags) on the floor, which is always "dirty." Then I use a disinfecting wipe in each hand, lifting objects to be disinfected from the container and wiping them all around and then placing on a paper towel (optional, but helps to spread moisture and dry the bottoms). That way there's not a "dirty hand" and a "clean hand," and there are no "puffs" of virus from the dirty items that are right next to the clean items on the countertop. And I get some badly needed exercise!

Anthony19572   April 20, 2020
A potential problem with this method is that shoes have been shown to pick up and carry coronavirus and the pathogens, so placing them on the floor as your prep area may increase the pathogen load that needs to be disinfected. A bleached tabletop then covered with fresh plastic on the clean side is probably safer.
I also take thin plastic painting tarps (disposable) and COMPLETELY line my shopping cart. I never use the check-out belts, I use self-checkout (even if I exceed the limit of items, not a problem at 7 AM) disinfect the bins and everything my take out bags will touch.
Cross-contamination is a real problem

G19380   April 9, 2020
for all those using disinfecting/sanitizing wipes, keep in mind these require a certain amount of "wet" contact time for true disinfection - often times the solution must stay wet on the surface for 4 minutes to disinfect it. the required wet time is listed on the back of the container.

Sandy19554   April 19, 2020
DON'T use soap on produce--it can cause severe gastric upset if ingested. (That Grand Rapids family doc posted a revised YouTube video reversing his original recommendation to soak produce in a sink full of soapy water and then wash it with soap & water). Don't soak delicate produce (like lettuce or berries) because it could ruin it. Rinse under running water for 20 seconds, and you should be fine. (You can then blot salad greens dry with a paper towel, or dry it in a salad spinner).

Diana S19345   April 8, 2020
With refrigerated and frozen items, we can just do what seems most likely to control exposure to viable virus. In most cases, its the container thats the risk, not the food in it unless that food would have been exposed to handling or close air contact from people like a net bag of oranges. If an item is packaged in a waterproof container like milk, then it can be washed thoroughly just like your hands in soap and water or wiped down carefully with an effective disinfectant (clorox/water mix). If the packaging is not waterproof, that item can be simply transferred to another clean container being careful not to cross contaminate the clean container with dirty hands, etc. Whether you choose to also wash the contents before it goes into a clean container depends on what it is. Some examples: I wash sealed milk jugs, glass/plastic jars with soap and water (or I wipe them down with paper towels soaked in a fresh clorox solution (4tsp plain bleach in 1 qt water) until wet and let them sit for 3-5 min then rinse with clean water. Carrots and celery are transferred to a clean new plastic bag. Frozen veggies are quickly transferred to a clean freezer bag and put in the freezer.
No matter what you do, there is a possibility the virus is on something in your fridge or freezer so wash your hands after handling things out of the fridge/freezer on a routine basis.

Marcia19312   April 8, 2020
Why are we not seeing UV light being used more? I read it kills the virus?   April 8, 2020
Ultraviolet light in the C spectrum (UVC) can definitely work but it takes time and you need to be able to expose all surfaces. See our CL Answer about UVC light for disinfecting

Joshua19360   April 8, 2020
I'm seeing many UV light wands for sale each day pop up on my feed. I'd like to get one for additional cleaning, but how do I choose?

Melissa19430   April 12, 2020
UVC is dangerous to the eyes, so one must become well informed and be very cautious with using it.

Marian19317   April 8, 2020
There was a report on a hospital using UV light to sterilize masks. I'm not sure how we bring that technology home.

Jannet19311   April 8, 2020
When I can't use alcohol I use garment steamer on many surfaces all this time. Unfortunately, I'm unable to test my results, but I do steam my N95, clothes, packaging, mail, etc
But now I'm wondering if my timing is completely off

victoria19428   April 12, 2020
Be careful with that. I've seen studies online (not for this particular virus but for disinfecting with a steamwand in general) that show most people hold the steamer too far from what they are trying to disinfect. I wonder if the company could help you with distance and duration. It's a great idea, so please report back if you figure out a method that works.

Stan19303   April 8, 2020
Re heating N95 masks after use: I would think you can't heat them in a microwave because of the metal nose strip or plastic parts that many of those masks have.
I wash my hands before putting my mask on, and then again before taking it off after use. Then I spray it with 91% rubbing alcohol before putting it away in a plastic baggie.
By the way I have begun taking quite a bit (5-6 capsules) of echinacea to strengthen immunity . Previously I had taken only one a day. Coincidentally (?) I have developed itchy patches on my arm- which I have never had before Nor am I knowingly allergic to anything. Has anyone else had this experience? Or is it perhaps all the extra disinfecting products being used?   April 8, 2020
Right - Don't microwave N95 masks. Also, don't spray or wet them, as this may reduce their filtering ability, as noted above. As to the itchiness you are experiencing, be aware that people can have allergic reactions to echinacea, particularly if they have allergies to sunflowers or other plants in the daisy family, as noted in the Concerns and Cautions section of our Echinacea Supplements Review.

Monica19307   April 8, 2020
Itchy elbow area is my reaction to gluten. I don't have celiac. My dermatologist recognized my gluten sensitivity right away by looking at it.

Michell19308   April 8, 2020
The itchy patches could be fungal,You may want to try an anti-fungal creme. Make sure your not irritating your skin and that it has plenty of time to dry which exposure to light and heat, like a gentle blow from a hairdryer prior to applying. You could also consider hydrocortisone with aloe, like itch-x, just a thin layer, uncovered after drying, mixed with a tiny bit of Lamotrin. Just a thought.

I also mix a little vitamin E oil sometimes with a few drows of lavender 100% essential oil if it's really a big area I'm treating for a long time.

But yours sounds small. Hope that helps. Sounds like the skin is just irritated and needs to be treated gently after cleaning, with general heat, or open to fresh air and if possible a little sunlight, then the creme.

I have absolutely no affiliations with these products. I have used them on myself and family with similar issues, many times saw the comment and thought I'd post.

TOM19463   April 13, 2020
As I commented above, I don't take echinacea, and hopefully the "rash" will go away if you stop taking it. Before considering an antifungal agent, (if the rash doesn't go away after stopping the echinacea), I'd have it looked at by your primary care M.D. or a dermatologist. (I have a PharmD degree.)

Sandy19314   April 8, 2020
Alcohol destroys the electrostatic barrier of the fibers on an N95 mask, rendering them much less effective.

Linda19318   April 8, 2020
I use echinacea only when I feel the first symptom of a cold or I will take it for a few days before I am going to fly on a plane or if I have been around someone that got sick, I'll take it as a preventative for a day or two.
I have noticed itchy patches on my arms if I take too many, say more than 2 a day for a few days. I already have a good immune system, so maybe that's why. Now when I use it, I only take one in the am and 1 in the pm. I rarely get sick (a cold every 3 or 4 years). I haven't had the flu since I was a kid, I'm now 67.

Stan19450   April 12, 2020
I am wondering whether the COMBINED effects of the supplements I take, many of which claim to boost immunity are causing an over-active immune system that may lead to itching... Starting today I am cutting out the extra echinnea (and alos Elderbery force) to see what happens, since those are the only two changes I have made erecently.

LYNN19325   April 8, 2020
STOP taking it. I had a similar reaction to just 3 caps. for 2 days, but all over my neck and face. I , too, read the scientific evidence that the herb has anti-viral and immune enhancing properties, and started taking it 2 weeks ago. Terrible red, hot, itching for 5 days until I finally went to the doctor. He reminded me how regular anti-itch cream could help and gave me a prescription for cortisone pills, just in case. I still have some itching, but the cream helped enough. It did sting for 5 minutes after applying. This is a warning from your body to stop. You could go into shock.

LYNN19326   April 8, 2020
Why not just wash the mask in hot water and detergent? Let it sit in the hot water, maybe in a bowl saved in the sink for only that purpose. Agitate with a stick you can throw out. You don't want to put your hands in really hot water with all the washing we're doing. Mine are dry and scaly. You shouldn't be using a mask for more than a day anyway because of all the bacteria we breathe out onto the inner surface.   April 8, 2020
Hi Lynn - We've added information about washing cloth face masks in the answer above, based the the CDC's recommendations.

Laura19330   April 8, 2020
According to Smart Air Filters blog, cleaning an N95 with alcohol or any liquid it seems takes the 'charge' (copper/zinc) out of the mask making it way less effective. You might want to look at their research, not sure if they recommend trying to 'clean' it at all, but do say that for general (likely non-medical I guess) that N95's are good for 20-30 days.

Stan19449   April 12, 2020
I will follow up on that lead, especialy since those of us who do have N95 masks should try to reuse them as much as possible to conserve them, assuming that they are still effective after being reused and sanitizied,
Healthcare workers would also need to know if and how they can reuse and sanitize their N95 masks if necessary.

Susan19338   April 8, 2020
I do react to disinfecting products, especially bleach. Just being in a room where it has been used recently makes a rash appear on my hands and it also makes my joints ache.

leonard19388   April 9, 2020
I don't recall the reason, but a video on protecting against the virus said that 70% alcohol is better than 90%. Perhaps someone will explain why in a comment.

TOM19461   April 12, 2020
It seems counter-intuitive, but 70% alcohol (ethyl- or isopropyl-) is more effective than 90+%. That's why the CDC recommends hand sanitizers that are 60-70% alcohol. (I have a PharmD degree.)

Muriel19485   April 14, 2020
that does sound counter intuitive. Thanks.

Jacqueline19563   April 19, 2020
Jackie: I, too, developed itching on the insides of my elbows during the days that I was taking 2 a day of Inner Defense essential oil capsules.

robert19302   April 8, 2020
picked up facemask at hospital as visitor.

hospital supplied mask when visiting patient.

i do not know what a N95 MASK is but do not think the issued mask is one.

can i use heat on this mask to use again??   April 8, 2020
Heat (as described above) would likely be fine for that mask.

Dawn19349   April 8, 2020
If it's an N95 mask it will say so clearly, on the mask

Barbara19301   April 8, 2020
I would assume using a sauna would help if you have mild covid 19. A hot tub also? I'm not a Dr. Just a thought :)   April 8, 2020
That's not likely to help a person with COVID-19.

David19300   April 8, 2020
I would be interested to know if *freezing* (as opposed to refrigeration) is an effective killing agent.

jane19361   April 8, 2020
I doubt that freezing would help, because labs use the freezer to store viruses (of other kinds) for study. Based on that, it seems likely that freezing would *preserve* the virus rather than killing it.

Jennifer19365   April 8, 2020
No - the virus likes cold temperatures. Try heat according to the guidelines from ConsumerLab (in this thread).

Linda19367   April 8, 2020
Sorry, I don't have a citation, but I remember reading a credible report that similar viruses can be preserved in a freezer for TWO YEARS!! Heat works, cold doesn't!   April 9, 2020
That is correct. We have added a citation to the posted answer.

Maureen19299   April 8, 2020
Thanks for all this info. My husband thought I was going overboard by putting ALL groceries outside on the picnic table and wiping everything down with Lysol before bringing in the house. Well, we just showed him!! LOL This whole thing just sucks.

Don19298   April 8, 2020
For even quicker decontamination you can place your food in a colandar sitting in a pot of boiling water with cover on, and steam it.
At a temp of 200F+ that will shorten the decontam time by x minutes.   April 8, 2020
FYI, there is has not been evidence of spread through cooked foods. Our information in this answer pertained more to surfaces on food packaging and other objects that could be contaminated.

Aleksandr19297   April 8, 2020
What about UV light? I am seeing cell phone UV light sanitizers advertised.
Thank you   April 8, 2020
Yes, UV-C light can work, but will also require time and depend on intensity, distance from object, light being able to reach all surfaces and not be shadowed, etc. We are looking into this further.

John19382   April 9, 2020
the type of UVC light that kills bacteria, is also very, very dangerous for eyes and skin. Be very cautious if you are using true UVC light.

matt19296   April 8, 2020
Hey, the "do not refrigerate" notation is helpful, but also need more detail. Say I bring home a carton of egg whites...plastic coated cardboard container. It should stay refrigerated to maintain freshness and elongate shelf life. How long should I keep it out of the fridge? Is the 20 minute ride home from the store good enough? Another 15 minutes? I know there's little science here, but we need some kind of guidance, not that you've opened up this can of worms. :-)

Matt Kayhoe   April 8, 2020
Wipe down the outside of the container with a disinfectant, then you can safely refrigerate.

Mary19565   April 19, 2020
ONce you have frozen something- can you take it out and disinfect it if it's in a package?

I only started disinfecting my groceries this past week/ there could be something in the freezer
that I should be able to thaw and disinfect???

Bonnie19328   April 8, 2020
wipe off the outside of the container with a disinfectant wipe.

Joyce19295   April 8, 2020
I was putting my wool gloves and paper masks in the micro wave oven to kill the virus and save on replacements. It worked well for a few times but I mistakenly hit the wrong button and had a little fire. Works if you only do ten seconds   April 8, 2020
Thanks for sharing that. To be clear, our information above refers to warming in a conventional oven, not a microwave.

Bonnie19329   April 8, 2020
microwave ovens work differently than a conventional oven. Why not just place them in the conventional oven at 150 degrees? much more even heating and better control over temp.

sandra19640   April 22, 2020
How many teaspoons of bleach in a 16 Oz glass bottle sprayer do you mix with water to sanitize packages/ surfaces? The oven tip for prepared delivered food is great. Been a member for years and so happy CL is keeping on top of COVID-19.   April 22, 2020
Hi Sandra - Thank you for your kind words, we are glad to hear you are enjoying your membership. The CDC recommends using 4 teaspoons of bleach per 1 quart of water ( Sixteen ounces is 1/2 a quart, so you would add half that amount of bleach -- 2 teaspoons -- to 16 ounces of water.

sandra19655   April 22, 2020
Thank you!

brian19293   April 8, 2020
Thank you for the information!

Chris19291   April 8, 2020
I have been applying a hot steamy iron to my face mask after each use, both front and back as well as ironing the board itself that the mask lays on. Is this a good method of killing the virus and saving the mask from multiple washings?   April 29, 2020
Microwave steaming of certain masks under controlled conditions has been reported by the CDC (see but there does not appear to be information on other steaming methods.   April 29, 2020
Microwave steaming of certain masks under controlled conditions has been reported by the CDC (see but there does not appear to be information on other steaming methods.

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This CL Answer initially posted on 4/8/2020. Last updated 8/11/2020. members may submit questions to We read all questions and try to answer those of popular interest.



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