Early on before the panic buying started I bought a box of N95 masks. We only use them when we go out, and we're not directly exposed to infected people in our home. So we don't need a ton of them. But disposing of them after one trip to the grocery store seems a waste.

What if this goes on much longer? You can hardly find them now. Can they be re-used? Can they be sterilized? I thought of a number of methods: microwave, alcohol dip, wash with soap and dry.

The bottom line: no, those sterilization methods are undesirable. The completely effective thing to do is just let the mask sit. Why? Because the virus body has a limited period of viability measured in all cases of less than a week. (Note: detecting a virus body is one thing. Detecting a viable (active) virus body is another. We've known that all along. The virus can't live forever outside a host. Eventually it becomes unviable.)

So, after use we'll 'quarantine' our masks for at least a week. Probably on the porch in unfiltered sunlight. (UV light also damages the virus, but can't solely be depended on.) Here are two articles for reference.

Does microwaving disinfect masks?

What is a reliable way to disinfect masks?

I’ve been 3D printing Montana mask “shells” that have an ~2 square inch filter port - cutting the filter section out of worn n95 masks:

https://www.makethemasks.com/

I’m able to make 3-4 Montana masks out of the material from one N95.

 

 

I have been spraying my masks with high purity alcohol after each use.  Wetting them but not soaking them. 

Remember to sanitize your hands before you put a "clean" mask on, and before you take it off, and again after you have taken it off.  It seems a bit extreme but it's the only way to avoid cross contamination.

EDIT:  Here is everything you never wanted to know about disinfecting, sterilization and inactivation of viruses on masks.

https://www.cdc.gov/coronavirus/2019-ncov/hcp/ppe-strategy/decontamination-reuse-respirators.html

 

You can sterilize any mask.

Put in oven at 170, bake for 30 minutes.

Much hotter and you will degrade the elastic.

Sars-1 lasts 15 minutes at 132 degrees.  At 170 degrees, the time is probably a minute or less.  Sars 1 and 2 are close enough that they probably behave in the same fashion.   The Sars-cov-2 virus is encased in a lipid sheath.   Lipids are fats.  Dissolve fats, dissolve virus.  Heat does a number on fats.

Liquids however can damage the fibers of the masks over time so they are not as desirable.  A squirt here or there isn't a problem, but repeated use of alcohol will definitely negatively affect it.

 

 

Yes I saw those temperature references in the articles. And heat makes a lot of sense, as long as the mask remains intact.

We are just leaving ours on the dashboard of the car in the sun.  They will bake there for a few days before we go out again.

1 hour ago, Tunaman said:

We are just leaving ours on the dashboard of the car in the sun

That's like asking someone to break your window.  Cars have been broken into for hand sanitizer.

7 minutes ago, Scorpio64 said:

That's like asking someone to break your window.  Cars have been broken into for hand sanitizer.

I dunno, that’s like sharing a condom vs lube

1 hour ago, Zeke said:

I dunno, that’s like sharing a condom

What's a condom?

I would agree with you that it's wasteful to get rid of a mask after you use it for a few minutes.  I believe a week in the sun is more than sufficient.  You would probably be OK with just a day or two. 

14 minutes ago, Scorpio64 said:

What's a condom?

Look hand sanitizers thievery I get, but used mask thievery is a special kinda stupid 

So at some point I know I have to go back to the office - Midtown - most likely mid may or so I bet...

I will plan on performing the same weird rituals that maybe or maybe not kept me safe, from late jan - march 11, which was my last day.  Those rituals did not involve masks.

I am going out on a limb that anyone going back to the city will be required to mask up.  Also I ride a NJ Transit bus to and from PA.

I also have a 3m 6200 half face mask with NIOSH 6100 cartridges - which seem to be charcoal laden with cloth initial filters.

Filters are unobtainium - but I found some 2091 Filters NIOSH P100's - lets see if they arrive.

The plastic cover comes off to access the pre-filter - for large particulate matter -  I was thinking of prefabbing additional disposable coverings - as the pre-filter before the charcoal that can be quick sprayed with alcohol then disposed.

 

Thoughts?

If all the filters dry thoroughly for more than 72 hours, or are heated to 150F for a half hour, either inside or outside the mask, any virus clusters should be inert. The virus just needs enough time and/or encouragement to deactivate. Adjust time parameters to your level of comfort.

An inert virus 'particle' is no more dangerous than dust.

BTW, I checked the 3M 8210 Plus mask specs (the ones I have) and the storage temperature peaks at 86F. So if I use heat I might limit the oven to 100F and just leave it in longer.

19 minutes ago, 45Doll said:

If all the filters dry thoroughly for more than 72 hours, or are heated to 150F for a half hour, either inside or outside the mask, any virus clusters should be inert. The virus just needs enough time and/or encouragement to deactivate. Adjust time parameters to your level of comfort.

An inert virus 'particle' is no more dangerous than dust.

BTW, I checked the 3M 8210 Plus mask specs (the ones I have) and the storage temperature peaks at 86F. So if I use heat I might limit the oven to 100F and just leave it in longer.

The mask minus filters I bet can be sprayed with a 70% Alcholol mix with water let sit and wipe....that is what we are doing for packages...it s pretty well built unit - jsut trying to get he most out of the cartridge being that are very hard to find now

27 minutes ago, USRifle30Cal said:

So at some point I know I have to go back to the office - Midtown - most likely mid may or so I bet...

I will plan on performing the same weird rituals that maybe or maybe not kept me safe, from late jan - march 11, which was my last day.  Those rituals did not involve masks.

I am going out on a limb that anyone going back to the city will be required to mask up.  Also I ride a NJ Transit bus to and from PA.

I also have a 3m 6200 half face mask with NIOSH 6100 cartridges - which seem to be charcoal laden with cloth initial filters.

Filters are unobtainium - but I found some 2091 Filters NIOSH P100's - lets see if they arrive.

The plastic cover comes off to access the pre-filter - for large particulate matter -  I was thinking of prefabbing additional disposable coverings - as the pre-filter before the charcoal that can be quick sprayed with alcohol then disposed.

 

Thoughts?

 

If you were so inclined a cloth booty over the filters that could get tossed would extend the life of the cartridges.   Like the things you get when you fly business class.  They fit just about every foot from children to adults.  Quite porous but do the job.

You can also use vacuum cleaner hepa bags, cut to fit under housing or even taped over the house.  Just pull off and toss.

 

 

1 hour ago, USRifle30Cal said:

The mask minus filters I bet can be sprayed with a 70% Alcholol mix

Hand washing with gloves in a bleach solution is probably better.  I was spraying my half face masks with alcohol, and after two applications became worried the alcohol may dry out the face piece and elastic headbands.

1 hour ago, Malsua said:

vacuum cleaner hepa bags

Capital idea Jeeves.

37 minutes ago, Malsua said:

 

If you were so inclined a cloth booty over the filters that could get tossed would extend the life of the cartridges.   Like the things you get when you fly business class.  They fit just about every foot from children to adults.  Quite porous but do the job.

You can also use vacuum cleaner hepa bags, cut to fit under housing or even taped over the house.  Just pull off and toss.

 

 

Just took a HEPA bag and I can get 4 to 6  skins out of the ones I have - !  great idea !

Thanks, Malsua!

Kenmore 53292 Style Q HEPA Cloth Vacuum Bags for Kenmore Canister Vacuum Cleaners 6 pack

It may depend on the type of mask.  I am used to using the  non-industrial types in the hospital I work at.  Our current practice is to wear them for entire shift unless they break or become visibly soiled.  Between uses, we are told to keep them in a paper bag, as a way to keep them covered, but also to keep them as dry as possible. I know there are different time speculations on the life expectancy of the virus, but the drier it is, the less likely it will survive.

Given the above, masks can be reused, but under the assumption that the outside of the mask may be, or is contaminated. 

3 hours ago, Malsua said:

Sars-1 lasts 15 minutes at 132 degrees.  At 170 degrees, the time is probably a minute or less.  Sars 1 and 2 are close enough that they probably behave in the same fashion.   The Sars-cov-2 virus is encased in a lipid sheath.   Lipids are fats.  Dissolve fats, dissolve virus.  Heat does a number on fats.

Haha suckers!

I just turned my thermostat up to 170. Now I just have to wait this out and I'm good to go!

1 minute ago, Handyman said:

Haha suckers!

I just turned my thermostat up to 170. Now I just have to wait this out and I'm good to go!

I was looking at the chart of Sars1 at various temperatures and the hotter the better.

They tested it at 5 degree increments and while it really shoots up over 110 degrees, there is still a difference between 70, 75, 80, 85, etc.

When my tenants left my rental property in Florida, I cranked up the thermostat to 85 and let it run a day at that.  I put in a wifi thermostat, so I changed the temp remotely.

Did they have CV?  Probably not.   Did it make any difference?  Probably not.  Did it make me feel better?  Yes :).   I also had my sister wait 4 days before she entered the house, just to be sure.

 

2 hours ago, Handyman said:

I just turned my thermostat up to 170. Now I just have to wait this out and I'm good to go!

Hey, I just heard Sweet Baby Ray's is a good antiviral.  Slather it on real good, it's uhh, uh, whatchacallit, a transdermal therapy.  Oh, and maybe, could you put some aluminum foil on the couch before you lay down.  And, for no particular reason, just leave the food dehydrator out..... Someone will be over to check in six to eight hours, if you are don... doing okay.

46 minutes ago, Handyman said:

Haha suckers!

I just turned my thermostat up to 170. Now I just have to wait this out and I'm good to go!

And you guys doubt the awesomeness that is crockpot 

Facemask Gumbo in a crockpot?

I guess I'll put this here, rather than opening a new thread. I hope you don't mind @45Doll? It seems closely related.

For those of us "bad preppers" who do not have formal masks, well... now the powers that be are saying even D-I-Y masks are a good idea on a trip to the grocery store, pharmacy, etc. Hmmm... it's hard to know what to do anymore... if any more guidance like this rolls in, I might end up wearing a hajib! 

Anyway, this first link has a video for a super-simple no-sew face mask using a scarf and ponytail holders, along with a number of links for other patterns, including a CDC link (which I listed separately) with both sew and no-sew patterns. They seem kind of clever, some even utilizing coffee filters. Now, mind you, I'm not sure how effective they are... but certainly, if you were asymptomatic yourself, it might help you from spreading the virus...? And I suppose it would also keep you from touching an infected surfacing and then touching your face and maybe transmitting it that way...? Anyway, you can decide for yourselves... I'm just providing the links!

https://www.msn.com/en-us/lifestyle/lifestyle-buzz/everything-you-need-to-know-about-making-your-own-face-mask/ar-BB122v9m?ocid=spartanntp

https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/diy-cloth-face-coverings.html

18 minutes ago, Mrs. Peel said:

I guess I'll put this here, rather than opening a new thread. I hope you don't mind @45Doll? It seems closely related.

For those of us "bad preppers" who do not have formal masks, well... now the powers that be are saying even D-I-Y masks are a good idea on a trip to the grocery store, pharmacy, etc. Hmmm... it's hard to know what to do anymore... if any more guidance like this rolls in, I might end up wearing a hajib! 

Anyway, this first link has a video for a super-simple no-sew face mask using a scarf and ponytail holders, along with a number of links for other patterns, including a CDC link (which I listed separately) with both sew and no-sew patterns. They seem kind of clever, some even utilizing coffee filters. Now, mind you, I'm not sure how effective they are... but certainly, if you were asymptomatic yourself, it might help you from spreading the virus...? And I suppose it would also keep you from touching an infected surfacing and then touching your face and maybe transmitting it that way...? Anyway, you can decide for yourselves... I'm just providing the links!

https://www.msn.com/en-us/lifestyle/lifestyle-buzz/everything-you-need-to-know-about-making-your-own-face-mask/ar-BB122v9m?ocid=spartanntp

https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/diy-cloth-face-coverings.html

The governmental thought process is that a bad or ineffective barrier is better than no barrier.  Unfortunately,  the mask/barrier becomes another thing to not touch that gets touched anyway.  I have been to stores where no one is coughing.  I don't buy into the theory that there is an abundance of people who are nonsymptomatic virus carriers.

34 minutes ago, Mrs. Peel said:

I guess I'll put this here, rather than opening a new thread. I hope you don't mind @45Doll? It seems closely related.

For those of us "bad preppers" who do not have formal masks, well... now the powers that be are saying even D-I-Y masks are a good idea on a trip to the grocery store, pharmacy, etc. Hmmm... it's hard to know what to do anymore... if any more guidance like this rolls in, I might end up wearing a hajib hijab!

Not a hijab Emma. You need a burka. Cover that face!

Emma Peel, 2020

Interesting new data.

Some guys tested piles of different materials.

Found out two layers of Blue Shop towels gets you almost to N95.

 

 

11 hours ago, Malsua said:

Interesting new data.

Some guys tested piles of different materials.

Found out two layers of Blue Shop towels gets you almost to N95.

I was also wondering about microfiber towels. I'll have to look into that.