How to reuse an N95 mask

When it comes to wearing masks during the pandemic, not all masks are equal in the protection they provide. From what I have read, cloth masks seem to provide the least protection, though they allow the wearer colorful options and the ability to make some kind of statement, though why some people feel the need to make statements through their attire is something that I find puzzling. The blue surgical masks appear to be better than cloth and the N95 masks are the best. But while the surgical masks are relatively cheap, the N95 masks are pricey (ranging from $1 to $3 each) and that raises the question of how long one can use them and whether they can be reused.

The good news is that the answer is yes, based on the fact that the coronavirus has a survival time of about 72 hours when outside a host.

Yes, reusing a mask is safe. Masks work the same way on any variant—by trapping virus-containing particles in their layers. Also, the coronavirus is transmitted mainly through respiration; you’re less likely to catch it by touching an infected surface. That said, it’s safest, and just good hygiene, to handle your masks with care, touching only the elastics and washing your hands afterward.

Though you may be tempted to rinse or wash your used disposable mask, even just to freshen it up, don’t try it. Getting the mask wet or agitating the mask with soap can damage the material.

“There’s no hard and fast rule,” said Sulmonte. The CDC paper-bag directive suggests discarding a disposable N95 mask after five uses. But that guideline was meant for workers in a healthcare setting. For everybody else, that may not be necessary. A mask is still wearable if its elastic bands continue to create a secure fit and the material looks clean and provides good airflow. (Dust, pollen, air pollutants, makeup, skin oils, and, yes, inactivated virus eventually accumulate and clog up the filter.)

Also think about where you’ve worn the mask and for how long. Someone who wears a mask in the subway every day, for example, may need to throw it out sooner than someone who wears theirs to the grocery store every once in a while. Whatever the circumstances, switch to a fresh mask if yours is dirty, thinning, damaged, or hard to breathe through, or if it no longer maintains a good seal.

The article says that if you cycle through several masks by using one a day while keeping the others in a brown paper bag in a dry, sunlit place (say a windowsill) for a few days, you are good to go.

It is interesting how the pandemic has resulted in me learning about things that it would never have crossed my mind to investigate before.


  1. Matt G says

    I stopped using cloth masks in the fall of 2020, and gave up surgical masks shortly thereafter. For the past 12 months I’ve used only KN95 and, for the past month, KF94. I live a low-risk life and will wear a mask until the material starts tickling my nose (generally 2 weeks).

  2. says

    I still use a cloth mask. However, it has an inner pouch, into which I have placed an appropriately cut-up high efficiency furnace filter. I wonder where this fits on the mask hierarchy. When it gets dirty, I remove the filter, wash it, and then insert a new filter into the pouch.

    With other masks (surgical, KF94), it seems most air flow is around the edges of the mask. Mine has an 18 gauge wire at the bridge of the nose to make it fit better there. It fits and stays way better than surgical masks for which I get a tremendous air leakage. The KF95 is better, but seems about on par with my cloth mask with inserted filter. Am I fooling myself?

  3. jrkrideau says

    @ 2 Intransitive
    I remember that first broadcast about the rice cooker and masks. I am still chuckling about the crack that the minister (?) did not do the cooking at home when someone had to show him how to turn on the rice cooker.

    To be fair it did look more like an airplane cockpit’s instrument panel.

  4. Pierce R. Butler says

    The blue surgical masks appear to be better than cloth …

    Unfortunately, I’ve had regular dealings on a regular basis with a major universite hospital for a while now. In the last few days, a certain facility’s receptionist -- and probably all the others’ -- now has to insist on everyone wearing a yellow version of that mask (same sort of papery material, to the sight and touch), on Strict Orders from The Administration, and offered me one to wear over my N95 (of a type for sanding & other dust-intensive work, apparently not up to medical snuff).

    No, she had no other explanations.

  5. steve oberski says

    ahucah @7

    Similar story about Ontario primary school teachers, not allowed to wear N95 masks at work, only cloth or surgical.

    Bureaucracy at it’s best, I believe this has since been changed to accommodate N95 masks.

    The big difference between cloth and N95 masks is the seal around the mouth and nose, cloth and surgical masks allow air in around the sides.

  6. garnetstar says

    achuah @4, the N95 and KF 94 and the like must seal tightly: your glasses shouldn’t get fogged at all when you’re wearing them, and the airflow should be such that there’s a slight deflation and inflation around the nose when you breathe. So, with those, you must adjust the nose wire and straps so that there is a tight seal.

    I had a research paper--sorry, can’t find it now--that showed that your 2-layer cloth mask with inserted filter layer was the best cloth mask of all, it blocked about 50% of incoming particles, must better than any other cloth mask. But, the well-fitting N95 and KF 94, etc., block out 95% and 94% respectively of incoming particles.

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