Skip to main content

N95s and KN95s: One and done?

EDITOR’S NOTE: As of June 2, 2022, current guidance does not recommend reusing N95 or KN95 masks. Learn more about use and care of masks from the Centers for Disease Control and Prevention.


As more and more people are looking to N95s and KN95s for better protection against the omicron variant of the SARS-CoV-2 virus, they’re wondering if these masks really are single-use. Or, are there safe and effective ways to clean or reuse these better masks?

While such masks are designed for single use, they can often be safely reused. According to Graham McKeen, assistant university director of Environmental Health and Safety, all you need to reuse your KN95 or N95 mask is a simple paper bag.

“As long as the mask isn’t visibly dirty, doesn’t have tears or holes, you’ve not knowingly had close contact with an infected individual and the mask continues to fit well, it’s OK to reuse for up to about five full-day uses,” he said.

McKeen recommends getting three to five face masks and three to five paper bags to cycle through. The key is ensuring that each mask sits 24 to 48 hours between uses to let any trapped viral particles die off.

How to store and reuse your N95 or KN95 mask

  1. Label each mask and bag with consecutive numbers (1-3, for example, if you’re using a stash of three masks). This helps ensure you’re using them in the right order.
  2. Wear mask 1.
  3. When you’re done wearing the mask, fold it and put it in bag 1.
  4. Next time you need a mask, wear mask 2. When you’re done wearing that mask, put it in bag 2 and so on, until you’ve cycled through all three masks.
  5. After you’ve used your last mask, go back to mask 1 and continue with the steps above.
  6. You can do this for about four rotations. After that, discard all masks and get a new set.

This is the only way to safely reuse N95 or KN95 masks. Plastic bags should not be used because they create moisture within the bag that can foster bacteria growth. In addition, these masks should never be washed like a cloth mask. Washing destroys the static charge these masks have that trap particles like viruses.


Want to make sure you’re getting a legit KN95 or N95? Get our tips.

Amanda Roach is a senior communications consultant with the Office of the Vice President for Communications and Marketing.