VERIFY: Sanitize your cloth masks in the washing machine, not the microwave

[SheltieLover]

[link:https://www.localmemphis.com/mobile/article/news/verify/verify-sanitize-your-cloth-masks-in-the-washing-machine-not-the-microwave/522-3ec18c5f-0fdf-4e8a-8f15-455641663699|

Social media posts claim you can sanitize your cloth masks in the microwave. But the CDC recommends you use the washing machine.

WHAT WE FOUND
A CDC spokesperson told VERIFY in an email, "The safe way to sterilize and clean a cloth face covering is in a washing machine."

A factsheet the CDC distributed on using cloth face masks goes into more detail. It once again says you should use a washing machine and talks about generally how often you should wash them.

It says they should be "routinely washed depending on the frequency of use." It doesn't delve into more detail than that.

[Siwsan]

1. Wouldn't ironing it also kill any virus?

It seems the heat from the iron would be as effective as a washing machine.

[TeamPooka]

2. there is no soap in that treatment. Soap is required

[Siwsan]

3. Ahhh. I thought heat, like an autoclave, would also kill the virus

Guess I'll be making a few more masks! Thanks for the info!

[TeamPooka]

5. The soap breaks down the protective fat layer surrounding the virus protein

exposing it to air and heat, then the heat destroys it.

[ProfessorGAC]

37. High Heat Destroys It Anyway

The lipid layer is a couple hundred nanometers thick.
It does not provide protection from heat. The thermal conductivity of lipids is reasonably high. Not like water, but not terrible. It does have a pretty high heat capacity or an organic compound.
So, ironing would work.
However, presuming the iron is around 100C, that level of heat would take 2 minutes (time required at 60C) divided by 16. Or 7.5 seconds.
I can see people thinking a couple seconds would be enough.

[eleny]

26. But food is made safe by the heat of cooking

So how do we make our food safe to eat if heat won't kill c19?

I've just been researching how to kill the virus if it's on food given how meat packing plants are starting to have problems with workers getting sick and dying from the virus. I posted last night about JBS packing located here in Colorado. So I went looking at food safety issues around c19. We have to get this right.

[uppityperson]

29. This virus is digested in the stomach after eating it.

[eleny]

31. I'd put that in the "cold comfort" file

Think of how many people are stomach acid challenged by their taking all sort of anti acid medications these days.

[uppityperson]

33. This virus can not survive the digestive process. At least it hasn't been found to so far

Don't inhale your food, swallow it. Even with antacids, the stomach is highly acidic and it changes to strong base in the intestines. This virus is digested.

[eleny]

34. "Don't inhale your food, swallow it"

We taste because we can smell it. Inhaling the fragrance of food that's an inch from their noses is something people won't be able to avoid. If you can taste it you've inhaled.

I've read that cooking food thoroughly will kill any c19 on the food. So well done meats are on the menu around here.

[xmas74]

4. You need soap and water.

https://www.cnn.com/2020/03/24/health/soap-warm-water-hand-sanitizer-coronavirus-wellness-scn/index.html

[Siwsan]

7. Then I could hand wash the mask, too, in hot soapy water.

I'm going to make a few more masks, just to have spares. I'm going to go on my first grocery mission, in a month, on Thursday. I have a mask, gloves, hand sanitizer and sanitizing wipes collected for the trip. Hopefully I can stock up on enough for the next 3 or 4 weeks.

[msongs]

25. yes hand wash, maybe put em in a pan with soapy water and boil a minute or two nt

[Nay]

30. That's what I do. Soap it up well with warm water and lots of bubbles, wash and scrub it by hand,

doing that for at least 30 secs. Then rinse well.

[eleny]

32. Me, too

It appears that it's the sure way to get the job done. Let the soap attack the fat in the virus and make it literally fall apart.

[Disaffected]

6. What is the best method of

sanitizing N95 masks? I have a couple of them, bought b/f the outbreak, and would like to use & reuse them.

[SheltieLover]

8. Sorry, not sure

Possibly UV-C light? I'm in same boat looking for answers. If I find something credible, I'll post!

[Disaffected]

11. As will I.

For now, I think I will spray with water (enough to moisten, not dripping) and nuke in microwave until the water steams off.

I have tried it and it seems to work well, as far as I can tell i.e. no apparent damage to the mask and it is good & hot when it comes out.

[SheltieLover]

13. TY!

[hardluck]

20. UV-C light is one way

In the test below an 8W UV-C light for 30 minutes was used to disinfect. They also tested other disinfection techniques.

https://m.box.com/shared_item/https%3A%2F%2Fstanfordmedicine.app.box.com%2Fv%2Fcovid19-PPE-1-2

[Sancho]

60. I've been using a UV wand....should work.

I asked some medical types and they also use UV sometimes, but caution not to look at the light. I only aim the light at the target per the instructions.

I've had the UV wand for years for use in hotel rooms, but I have no proof of how effective it is to kill viruses.

[hardluck]

19. Here you go

From Stanford Medicine Anesthesia Informatics and Media Lab. Goes through different ways to sterilize N95 masks.


https://m.box.com/shared_item/https%3A%2F%2Fstanfordmedicine.app.box.com%2Fv%2Fcovid19-PPE-1-2

[Disaffected]

21. Thanks for that.

It looks like placing in a 75C oven for 30 minutes works well, BUT, with the proviso that putting a contaminated mask in your oven might be a "good" way of spreading the contamination. I suppose that proviso however would apply to pretty much any disinfection method and any virus placed in the oven would perish along with that remaining on the mask itself.

But, yeah, if you happen to have an old oven sitting in the garage or basement, use that instead. Who knows for sure at this point? All one can do is go with the info that is available at the time...

[hardluck]

24. Any virus in the oven would die and you could always turn it up to a higher setting to be sure

The more likely scenario is potential contamination of the outside of the oven/kitchen area. Nothing is perfect but I think the oven route would work if you staged the masks on a cookie sheet outside to avoid potential contamination in the kitchen and then brought them over to the oven.

[dawg day]

51. Or take the mask out and then turn the empty oven up another 30 degrees?

The virus won't survive that, surely.

[KY_EnviroGuy]

28. N95s are not meant to be reused, so use caution.

The main thing is to not use liquid spray or cleaners that wet the paper material because that can break down the bonds holding the fibers in the correct array for trapping particles. Very strong UV rays may also damage the fiber structure, but that would need to be tested. Even handling them roughly can damage the filtration properties. The problem is that because they're not intended to be cleaned or used for extended perods of time, no one can officially publish a method and few labs are qualified to do those tests with live virus anyway.

The simplest way is to just store them away in a safe place for several days and the virus will expire on it's own, or possibly heat them in a temperature-controlled oven (which may also damage the fibers structure or shorten the life of the rubber head bands).

The Lancet Microbe seems to imply 5-minutes at 70 deg-C (160 deg-F) will do the trick, although I'm not clear on how or what they tested. Hell, I warm our dinner plates in a Breville toaster-oven at 170 deg-F.

See.....

Stability of SARS-CoV-2 in different environmental conditions
Alex W H Chin, Julie T S Chu, Mahen R A Perera, Kenrie P Y Hui, Hui-Ling Yen, Michael C W Chan, et al.
Published:April 02, 2020

Link: https://www.thelancet.com/journals/lanmic/article/PIIS2666-5247(20)30003-3/fulltext

The most disturbing thing I saw in Lancet's tests was that some viable virus particles were found in surgical masks after 7-days of storage at room temperature and humidity.


KY............

[SheltieLover]

62. TY, KY!

I'm afraid to reuse, personally.

[KY_EnviroGuy]

9. Soap and water works. I think many people believe it's too good to be true.

That's been on the CDC's list from the beginning. Soap and water denatures he virus.

If 20-seconds of scrubbing our hands with soap and water does the trick, then surely a run in the washer will too.

[SheltieLover]

12. Could be

I think this article was meant to counter idiotic non-fact-based soc media posts, KY.

Thanks for pointing this up, though. I think you are right! 👍

[KY_EnviroGuy]

36. Now that I've studied this a bit.....

for cloth masks, the best process might be to simply place them in boiling water for a few minutes. Coronavirus does not like heat and especially hot water. That should denature the virus quickly. I'm still searching for data on scientific tests on this specific virus, though. I always prefer any conjectures be confirmed by solid science.

Country folks where I was raised used to sanitize their clothes in a big black kettle of boiling water over a fire, so perhaps we could gain from that simple wisdom.

On a much higher scientific level, we can refer to....

Link: https://www.cdc.gov/infectioncontrol/guidelines/environmental/background/laundry.html

Damn, it's hard to find stuff on that web site and some of the language makes my head spin. But, it's there when I'm patient!


KY.............

[ProfessorGAC]

38. 7.5 Seconds At The Boiling Point of Water

It's 2 minutes at 140F, or 60C. At 100C, the decomposition of the virus accelerates 16 fold. Zero order reaction, so every ten Celsius doubles the rate.
So, it'll definitely work.
I'm unsure how many times the elastic would take the heat, though.

[KY_EnviroGuy]

40. Yes, it depends on what materials the elastic is made from, although...

even natural rubber is good to around 180 deg-F. Spandex and others would be different.

By your numbers, someone with an accurate kitchen thermometer could perhaps do 150 deg-F for two or three minutes and be safe. Best to agitate well though, in case of air bubbles or just give it more time (say, 5-minutes).

Would you please share where the test data you described (2 minutes at 140F) originated? I looked into that back in February (for food preparation at the time) and found little specific data for COVID-19, I assume because it's novel. Would love to have your reference to study and bookmark.


KY.....

[ProfessorGAC]

45. I'd Have To Search

It was posted as a link here (CDC?), at the time that idiot R state legislator said you could blow a hair dryer up your nose.
It stated denaturing began at 135, and would take 3 or 4 minutes to denature effectively. I extrapolated to 140F as a starting point and called it 2 minutes. Maybe it's 2.5.
I was dong back of the envelope.
Now, the actual, no guessing part:
But, the rate increase I described is not an estimate. That's exactly how zero order reactions work. So do 1st order, except in extreme conditions like very high heat or ultra high pressure (which are usually autocorrelated).
So, maybe its 8.3333 seconds.
Fair to estimate 7 to 8 minutes.
Also, because some bacteria are more resilient to temperature, microbiologists have long used a standard or 180F for 60 minutes, 150F for 4 hours, and 135F for 8 hours to get surfaces microbe free.
A lot of viruses are pretty susceptible to heat.
It's why the body releases pyrogens, which elevate body temperature, as a response to a virus.
Just a change or 2 or 3 degrees Fahrenheit disrupts reproduction in a day or so. You can imagine if the temperature goes up another 30 degrees. Or, 80.

[KY_EnviroGuy]

50. Thanks, Professor. That's good news because....

it means we don't have to super-heat foods we fear could have been contaminated from a store or restaurant. What we're discussing doing here is not much more than what I would normally do to reheat carry-out food.

Still trying to grasp how you arrived at the numbers, but I'll get there.

I suspect the odds of us getting enough viral load to infect from what accidentally got on food items is pretty slim but we feel more safe by going through the exercise of moderate heating.

Thanks again for the help!

[SheltieLover]

65. Thank you, Professor!

[catrose]

10. And if your mask has a metal nose piece (all the ones I make do)

putting it in the microwave is a REALLY bad idea.

[SheltieLover]

14. Yes, good point!

The few I have do. Ty!

[Disaffected]

16. Depends on the shape of the metal.

If the metal piece does not form a loop or two pieces separated by a small gap, nothing bad will likely happen.

I have tried it with my N95s (that have a metal nose piece) and the masks have emerged unscathed (as noted in a previous post, I first sprayed the mask with a little water). Now, the trick is not to leave the masks in too long as the fabric & plastic in the mask will eventually overheat. The best way is to try it for a few seconds at first followed up by longer stretches. I'm thinking that 30 seconds to a minute would be adequate but, keep an eye on it until you get a feel for what is OK.

Edit to add: As I understand it, N95s should not be washed in soapy water as it will remove an electrostatic coating that is on the filter fabric.

[SheltieLover]

17. TY!

[catrose]

41. There's a photo circulating the internet of a homemade (I think) pleated mask

that went through the microwave. The owner needs at least a new mask (not sure about the microwave).

This is the type of mask that needs soap & water.

I understand that someone's figured out a way to sanitize N95s, but it looked like an industrial process.

Not being in the medical field, I don't expect to have my hands on an N95, but I'll keep your advice in mind.

[Disaffected]

42. The trick is not to leave it

in the microwave for too long at too high a power setting. Even dry fabric will eventually get hot enough to ignite and plastic hot enough to melt and/or ignite. I found that out the hard way by trying to dry hiking boots in the MW - did not keep a close enough watch and burned & melted part of the insole.

Heating a dry object in the MW (or running it empty) is also hard on the oven itself - the microwaves are not readily absorbed, reflect around the interior of the cabinet and back into the magnatron (the device the generates the the microwaves) heating and damaging it.

Putting gerbils in a microwave oven is also not a good idea.....

[catrose]

43. Or potatoes. Microwaves have their uses, but...

[Disaffected]

44. Potatoes?

I frequently cook whole new potatoes in the MW. Let them steam and scream until soft throughout and the skin is a bit wrinkly.

Then cut up and brown a little with a bit of ground pepper in a skillet - moist, fluffy and yummy!

OTOH, eggs in the unbroken shell - don't even think about it.

[kimbutgar]

15. I wonder if using one of those clothing steamers works?

I made some masks for my hubby and washed them in my washing machine yesterday.

[SheltieLover]

18. Not sure

I would go with soap & hot water, but mine are not fabric. Bought a few N-95's long ago.

[PeaceNikki]

22. You can steam, but it has to be for 10 minutes.

A rice cooker is an option.

[kimbutgar]

23. I have a food steamer that I use to reheat food rather than use the microwave

I wonder if that would work?

[cwydro]

27. Better yet, don't go out unless absolutely necessary.

Then you’ll not need to worry about it.

[Disaffected]

35. I do wonder about the mail and newspapers though.

I don't get a newspaper any more but the mail still comes. I spray it with a bleach solution and let it sit for a while before opening it. Same for parcel delivery.

[applegrove]

39. Coronavis is protected by a layer of 'fat' that detergent or soap just destroys.

Nobody puts soap on their mask when they put it in the microwave.

[ProfessorGAC]

46. A Science Note On This

I'm not surprised to see this.
MedTech microwaves are likely tunable, so the exact frequency can be dialed in to the resonant frequency of the hydroxyl in the protein head.
Consumer microwave oven are fixed tuning, and the frequency is aimed at the dipole moment of water.
There's no water in the virus, or any to speak of in the mask.
So, putting the mask in the oven probably doesn't heat the mask very fast.
Since it's not tuned directly to the virus, and the mask won't get super hot, it makes sense that it's better to wash them.

[SheltieLover]

47. TY!

Do you know what the mortal oscillary rate of the virus is?

[ProfessorGAC]

48. Alas, I Do Not

But, those folks in that Ohio lab DeWine talked about probably do!

[SheltieLover]

49. TY!

I would think if we could get the freq, a freq generator should be able to sanitize!

[jberryhill]

52. .

You might want to read this


https://www.tandfonline.com/doi/full/10.1080/0307945042000205874

Replicate swabs were placed in a microwave oven (Sharp R-772(W)M), for varying lengths of time at maximum power (900 W).

And this:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5114683/

[ProfessorGAC]

57. I Did

I stand by what I said.
They did not check adsorbed water content of the substrates.
If they just have a milligram of water, it's the water heating up.

[jberryhill]

59. In five seconds?

There’s some ambient moisture everywhere just from humidity, for that matter.

[ProfessorGAC]

61. You're The One Who Mentioned Bulk Temperature

In the other post. At the molecular level, steam is steam.
I will acknowledge that some nucleic acids are short chain with double bonds. Those double bonds would be susceptible to excitation from microwave.
The industry experimented for a while using microwave oven for solids testing.
Things with carbon-sulfur bonds, or C-O-S bonds would char. The electronegativity of those bonds were highly excitable, but there is little to none of those sort of bonds in cotton, paper or viruses.
I will stand corrected if the results show that the nucleic acids were fractured in the virus. I don't envision the spectrochemistry that denatures the protein in this amount of time.
The most sensitive bonds are those with an exposed oxygen. It's why alcohol or sugar heats up.
Absent the hydroxyl or ether linkage, the excitation is highly unlikely.

[jberryhill]

53. Also, the notion that microwave ovens are "tuned to water" is a popular myth

It’s simply not true. They are broadband radiators.

https://wtamu.edu/~cbaird/sq/mobile/2014/10/15/why-are-the-microwaves-in-a-microwave-oven-tuned-to-water/

So how do microwaves in an oven heat food if they are not tuned to a specific resonant frequency of water? They heat the food through simple dielectric heating. In dielectric heating, the electric field in the electromagnetic wave exerts a force on the molecules in the food, causing them to rotate in order to align with the field. Because of this rotating motion, the molecules collide into each other and convert their somewhat ordered rotational motion into disordered motion, which we macroscopically call heat. Many types of molecules in the food absorb energy from the microwaves in this way, and not just water molecules.

[ProfessorGAC]

56. 95% Water

Anything with a terminal hydroxyl will excite as well.
This article is only partly true.
Carbon chains, or rings, including those with nitrogen atoms, will not heat at significant rates in a consumer microwave.

[jberryhill]

58. That's neither here nor there

A consumer microwave oven has proven effective for inactivating a coronavirus in as little as five seconds:

https://www.tandfonline.com/doi/full/10.1080/0307945042000205874

That’s got nothing to do with bulk heating.

[Doreen]

54. I must be the only one who does not have my own

washer and dryer or can"t afford to use the pay laundry enough times to keep my mask ( if I had one ) clean the way it is supposed to be kept clean.

I have one mask and it is not a reusable even though I do reuse it. I only use it around my mother when I do have to take her places ( bank, doctor. )

My mother has a couple of masks but she also has her own washer and dryer.

If lysol spray existed any more I would spray my mask with it each time I was done and hang it until I needed it next.

No matter how I would like to do all of this I just can't.

[LisaL]

68. You can't wash non reusable mask anyway.

Cloth masks can be washed by hand with soap and water if washing machine is not available.

[brooklynite]

63. Why would you sterilize ANYTHING in a device where you prepare your food?

..and why would you pay attention to what "social media posts" tell you?

[SheltieLover]

66. Personally, I would not, on either count!

I don't use social media & I don't try to reuse the few masks I have. I would be nice if they could be sterilized though! 👍

[Dem2]

64. I use soap and scalding hot water in my kitchen sink

Last edited Tue Apr 14, 2020, 12:04 PM - Edit history (1)

But yeah, I agree soap should be used to ensure any virus is destroyed.

[SheltieLover]

67. And

Last edited Tue Apr 14, 2020, 12:31 PM - Edit history (1)

If one doesn't care about the appearance and can find bleach (?), I would dump some of that into the wash water as well.