Everything You Need to Know About Cleaning Your Face Mask, According to a PPE Expert

With protective face masks in short supply and high demand, it’s more important than ever to conserve them. But with so many guidelines out there, it can be hard to know exactly which measures to take to ensure you’re using your mask both safely and effectively. For example: How many times can you wear a mask to the grocery store before you need to disinfect it?

Related: The Ultimate Guide to Buying Masks for Wearing to the Grocery Store (and Beyond)

According to Jade Flinn, a nurse educator for the Biocontainment Unit at Johns Hopkins Medicine who specializes in personal protective equipment (PPE), a good rule of thumb is to treat your mask like you treat your undergarments.“I always recommend that you change your mask like you change your underwear: daily,” she says.

Once you take your mask off, what do you do with it? That depends on what type of mask you’re wearing. Here are some tips from Flinn for cleaning and sanitizing your different face coverings.

You can launder DIY cloth masks or bandanas in the washing machine, but Flinn suggests washing them separate from your other garments. (Hair ties or other elastics can be thrown into a mesh bag and washed, too.) Opt for the hottest setting on both your washer and dryer, and use regular laundry detergent according to the instructions — those precautions should be enough to kill germs lurking on your mask.

Another important point Flinn makes: Be conscious of which parts of the mask you do and don’t touch in any part of the removal, sanitizing, or discarding process. Consider the exterior of the mask, and your hands, soiled after going out in public. “When you wear PPE, there should be a mindset change where you’re a bit more conscious of your environment,” she says. “It’s important to be aware of what you are touching.”

Read more: The Easiest Way to Make Your Own No-Sew Cloth Face Mask

The first thing to keep in mind: When possible, N-95 respirators and surgical masks should be preserved for healthcare workers who need them. If you happen to be in possession of either type of mask, you can re-use them as you need to, but don’t throw them in the laundry. Instead, time is the best way to sanitize a mask you want to reuse.

Flinn recommends hanging a contaminated mask to dry, or leaving the mask in a paper bag for 72 hours before wearing it again (that’s the longest amount of time the coronavirus is expected to live on any surface). If you have more than one mask at home, it’s a good idea to rotate them: While one mask is de-germing in the paper bag, use another one if you need to go out for essential errands, then grab a fresh paper bag and swap them out.

Paper is important here, because it’s a breathable material. Flinn says that she’s heard some people are leaving their masks in plastic bags when they’re not being worn, but that practice could have negative consequences: “Plastic bags are an incubator for whatever fluid was inside of the mask,” she says.

You can use the bag trick several times (with clean bags) to re-wear one mask, but keep an eye on the integrity of the mask to make sure it’s still going to block out airborne particles — more on that below.

While UV rays can technically zap pathogens — some health care facilities use special UV equipment to disinfect masks — Flinn says it’s not a good idea to try sanitizing your mask by leaving it out in the sun. This is especially true for surgical masks and N-95 respirators. “There’s a piece of foam at the bridge of the nose, which could disintegrate in sunlight,” she says. 

A steamer can be a great way to disinfect some garments, like sheets, but skip the steamer when it comes to your mask. Flinn says theoretically, steam could be effective in disinfecting a mask, but it’s not a good idea to roll the dice on PPE. Every steamer is different, and there’s no way to know whether you’re using enough heat or humidity to kill the virus. Plus, she says, masks are multi-layered, and the steamer will only penetrate the surface. Washing in the laundry is a more reliable way to get the gunk out of the masks’s fibers.

A few signs that your mask — surgical, N-95, or cloth — is ready to toss: If it’s visibly soiled, if there’s obvious wear on fibers, or if any part of it is damaged, including the ear loops. When it’s time to discard your mask, Flinn recommends throwing them in a trash can in your home. It’s best to use a trash can with a lid (like your kitchen garbage rather than your bathroom bin) to avoid re-aerosolization if the can is disturbed. Or, you can just take it out to your outside garbage immediately. Make sure, as always, to wash your hands thoroughly after coming into contact with anything that could be contaminated.

This originally appeared on Apartment Therapy. See it there: 5 Things You Need to Know About Cleaning Your Face Mask, According to a PPE Expert