Should you sterilize your facemask in the microwave?

July 23, 2020

After the Centers for Disease Control and Prevention (CDC) and now local and state governments have recommended that people wear a face mask if they are in any public setting, more and more people have been wearing them.

Since masks such as N-95 respirators have been in short supply and mostly only available to health care workers, people have been creative by making their own cloth masks out of a number of materials including cotton fabric, mesh cloth and other things. Most of these masks that people create are one-off and they are expected to use them again and again.

But while many Americans have turned to do-it-yourself templates to make the cloth face coverings, not that many people seem to know what to do with them to clean them.

So that has left room for a number of “theories” and myths on social media how to effectively clean your mask.

One post on social media suggests that you put your mask in the microwave in order to disinfect it. Now, while that may sound halfway like it makes sense, it’s actually incorrect. Correction: it’s flat-out wrong. The cloth can actually burst into flames.

The Las Vegas Fire Department could attest to this. They posted an alert surrounding this issue:

“Reports of fires starting across the country in microwave ovens after people put their face masks in them to sterilize them. Never put anything in a microwave oven that is not recommended on the packaging. That includes face masks.”

A microwave will indeed heat up the water in the clothes, which may in places become hot enough to burn the clothes. The microwave will not only heat up water molecules ON the clothes, it will also heat molecules inside the clothes, i.e., inside the fibers.

Just look at your socks as an example. If you microwave your socks you can see the same thing happen. Anything with elastic can potentially set fire to the cotton material your clothes are made of.

A CDC guide to mask use suggests the cloth masks be cleaned regularly, and that they should “be able to be laundered without damage or change to shape.”

How should you clean a cloth mask? The University of Utah offers some great information about how to make, use and clean a cloth mask.

According to the site, the best way to sanitize a mask is to launder it in your washing machine in hot water using a detergent that leaves no residue, then drying it in a hot dryer.

The soap, hot water and heat from the dryer will kill Covid-19. You have to think: if the CDC says that washing your hands and using hand sanitizer is good for fighting Covid-19, why wouldn’t simply washing the garments you wear, like a mask, also be good?