Clean N95 dust mask

[Jim Allen]

I use N95 mask in my shop, they used to cost less than $1 apiece, now they're $7.80 apiece. Anyone know of a good way to clean them? I only have 2 left, and I don't want to experiment with them.

[Frank Pratt]

Firstly, check prices again. They have come down considerably. Consider using a proper face mask with replaceable cartridges. Comfort and sealing are a lot better, and the cartridges can easily be cleaned by using a vacuum to suck air through backwards. I use a North mask & the cartridges I'm using now are a couple of years old & still good. A pair is less than $10.00. And go with N100, or HEPA, filters. If your gonna wear a mask, you might as well wear one that will get more of the smallest (and most dangerous) particles

[Jamie Buxton]

There have been articles recently about cleaning N95 masks in a common kitchen microwave. Scientists say it works. Here's one from WebMD -- https://www.webmd.com/lung/news/20200709/study-sterilize-n95-masks-with-a-microwave If you want to dig back to the original paper, it is -- https://mbio.asm.org/content/11/3/e00997-20

[Jim Becker]

KN95 masks are pretty available at this point, if you prefer to use that kind of mask in your shop, and provide the same level of filtration as the N95 masks. That said, I prefer to use a mask that's designed to be cleaned for dust protection in the shop and bought an RZ awhile back for that.

[Jim Koepke]

There have been articles recently about cleaning N95 masks in a common kitchen microwave. Scientists say it works. Here's one from WebMD -- https://www.webmd.com/lung/news/20200709/study-sterilize-n95-masks-with-a-microwave If you want to dig back to the original paper, it is -- https://mbio.asm.org/content/11/3/e00997-20

Be careful with that. Some of the masks have staples to hold on the straps. Some may have an aluminum piece to shape over the nose. Metal in a microwave is not a good idea.

jtk

[Dan Friedrichs]

What are they "dirty" with? As long as you can breathe through them, they continue to be effective.

[David Bassett]

Be careful with that. Some of the masks have staples to hold on the straps. Some may have an aluminum piece to shape over the nose. Metal in a microwave is not a good idea.

jtk

Also, microwave, oven, UV, etc. cleaning are to kill viruses which is different than unclogging and rejuvenating a dust clogged woodworking mask.

[Erik Loza]

I just discard them once they start to get fuzzy on the inside or when the elastic starts to feel weak. We have some “higher-end” fabric ones I throw in the washer but the KN95’s I always considered disposable.

Erik

[Osvaldo Cristo]

I had four 3M N95 with including valve remaining in my shop. I spent today one. Now I have only three.

As other warned, prices went down from peak. Currently in Brazil I can find them at USD 2.50 each.

Be warned they are not recommended for COVID use as although they will protect the user, the valve will not contain the eventual virus the user have launching they at surrounding atmosphere but they are my preferred at woodworking.

I do not like rubber face mask even it is way more convenient to change the filter element.

[Bill Dufour]

If you just want to sanitize them hang them in the sun for one afternoon.
Bil lD

[Scott Winners]

N means not petroleum resistant and 95 means 95% of particles under 5 microns get filtered.

P means petroleum resistant.

In the shop I use (somtimes) a 3M respirator (rubber framed mask) with either a particulate filter or an organic solvent filter depending on whether I am sanding teak or slinging epoxy.

If you are just working in the shop with wood dust a particulate filter should neet your needs.

[Jim Allen]

Thanks, it look like it time to use my respirator (3M 07193) until things cool back down. The N95 are either way too expensive or not available at all. Found the KN95 at Amazon for $113 for 50, but by the time I went through 50 masks the N95 would be back to a reasonable price. Filters for the respirator are still reasonably priced.

[Jim Becker]

Tool Nut has KN95s in stock for very reasonable prices.

[Jim Allen]

Thanks Jim, they are on the way to Lakeside!

[Jim Becker]

Happy to help.

[Ole Anderson]

And the K in KN95 means they were made in China to Chinese standards. FYI. I have a 3M 8246 R95 that I bought for cleaning the shower as it has a charcoal layer for absorbing light acid fumes. Been wearing it so long to go shopping it looks grubby, but it now fits like an old pair of jeans.

[Brian Elfert]

I have a 3M full face respirator with a set of P100 particulate filters and a set of vapor filters. I use that respirator in the shop with whichever filter set is appropriate for the job. The filters seem to last forever. Besides, I don't think you can get real 3M P100 filters at all right now. There are a lot of imitation filters that may or may not filter properly that also tend to be very expensive right now. It seems like the vapor filters are still good as I can't smell the vapors once the respirator is on.

I saw a chart comparing the KN95 and the P95 masks. They are very similar and I would have no problem with a KN95 mask as long as the manufacturer is making them to the standard and didn't cut corners. The KN95 actually filters some particle sizes slightly better than a N95 mask. There was a small business locally that managed to get an entire container or two of KN95 masks around April 1st of this year. They were selling them for $4 each and I think you had to buy a case of 1000 so $4,000 worth. They were donating 100 masks for every case purchased. The company got reamed on social media for charging so much for masks and for not donating them all to healthcare.

[Bill Dufour]

Do not use fabric softener when washing them. My wife did and I can no longer use that mask. It fogs up my glasses. Same reason to not use softener on towels. It clogs the pores and leaves a waxy substance behind so it no longer absorbs water or allow as much air to pass through the fabric.
Bil lD

[Brice Rogers]

I cleaned a couple of my N95's. These were ones only used in my workshop so I was just looking for a cleaning and wasn't looking to sanitize them for Covid.

First I used compressed air and blew out the wood dust from the inside. Then I did the same on the outside and then again on the inside. Then I squirted them with some spray cleaner and gently massaged them. Then rinse, then re-spray, then rinse. Then I let them dry for a day or two. Other than looking perhaps a little fuzzy, they looked like brand new.

[Jim Allen]

Thanks Brice, even though I've purchased some KN95 masks I will try that and see how it works. What kind of spray cleaner did you use?

[David Bassett]

I cleaned a couple of my N95's. These were ones only used in my workshop so I was just looking for a cleaning and wasn't looking to sanitize them for Covid.

First I used compressed air and blew out the wood dust from the inside. Then I did the same on the outside and then again on the inside. Then I squirted them with some spray cleaner and gently massaged them. Then rinse, then re-spray, then rinse. Then I let them dry for a day or two. Other than looking perhaps a little fuzzy, they looked like brand new.

Be careful with those. A study, for Covid sanitizing, compared different methods and retested the mask's filtering ability to check for degradation. (I think it was Stanford Med Center, but don't remember. It was last March or April.) The masks went from the spec 95-100% effectiveness for particles down to the low-40s range for most (all?) liquid cleaners. You aren't concerned about killing viruses, but the filtering efficiency will affect dust protection too.

[Frank Pratt]

Be careful with those. A study, for Covid sanitizing, compared different methods and retested the mask's filtering ability to check for degradation. (I think it was Stanford Med Center, but don't remember. It was last March or April.) The masks went from the spec 95-100% effectiveness for particles down to the low-40s range for most (all?) liquid cleaners. You aren't concerned about killing viruses, but the filtering efficiency will affect dust protection too.

I read 2 or 3 different sources on mask cleaning studies and they all had the same result. Washing them greatly reduces the filtering efficiency.

[Brice Rogers]

Thanks Brice, even though I've purchased some KN95 masks I will try that and see how it works. What kind of spray cleaner did you use?
I think that I might have used Chlorox tub and tile cleaner. It is actually like half or quarter strength bleach.

[Jim Allen]

I received the KN95 masks from Tool Nut today, I can only report on their comfort, which is minimum, the straps go around the ears, interfering with the glasses and not a significant seal around the nose causing the glasses to fog up. They are better than no dust mask, but not very comfortable.

Thanks everyone for your comments and suggestions.

[Jim Becker]

Paul, if you're not happy with them, let them know. Perhaps they will do something for you. And I can appreciate the issue with behind the ears...I can't wear a mask that is that way because of my hearing aids and my cloth masks (not shop use) tie on without engaging my ears.

[Ole Anderson]

I threw my p95 mask in the wash. I might have lost some filtering efficiency, but it is still better than most homemade solutions or the common blue surgical style mask.

[Stan Calow]

Here's a current article in Newsweek on how to sanitize KN95 masks: https://www.newsweek.com/amplify/how-sanitize-kn95-masks-50-minutes-are-they-safer-n95-masks
Point being that you can sanitize to kill viruses on the mask, but not to wash them to clean from dust.

[Jim Allen]

My wife's a quilter, she's probably made over 300 masks for people in our community and all of our family throughout the country. I explained my problem to her so she converted the KN95 masks to N95 sans valve.
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[mike stenson]

Not all N95's have an exhaust valve, it's a part of neither specification. But, I'm also not a huge fan of the ear loops (not all KN95's are ear looped either, for that matter and like n95's some have exhaust valves).

[Stan Calow]

Not all N95's have an exhaust valve, it's a part of neither specification. . .

That's true. I had some that don't in the shop.
For those of you that use RZ masks in the shop or elsewhere, they now have some caps you can replace the valves with.