By Paul M. Dake, M.D.

Q: My wife made me a face mask to wear when I’m out of the house, using instructions she found on the internet; is there any way to quickly sterilize the mask, short of putting it in the washer?

A: There is. Because of a shortage of face masks for health care workers, there has been great interest in finding ways to reuse the face masks.

In a very carefully done study published on 4-22-20, by the Department of Pathology at the Beth Israel Deaconess Medical Center & Massachusetts General Hospital, both in Boston, in association with Harvard University in Cam-bridge, Massachusetts, it was shown that N-95 masks, which are the types worn by doctors & nurses dealing with patients with highly infectious diseases, can be sterilized for reuse up to 20 times, without affecting their ability to filter out virus particles or their fit to the wearer’s face.

There are a number of methods that can be used, but nearly all of them rely upon equipment not readily avail-able to the average homeowner, or upon carcinogenic chemicals. The study focused on a new method that used only readily available household items.

It requires the use of a 6.5-inch by 6.5 inch by 3-inchdeep Pyrex baking dish, with a mesh stretched over the top, held in place with a large rubber band; the mesh from a supermarket produce bag works perfectly. Pour one quarter cup of tap water into the dish, place the mask to be sterilized on top of the mesh, making sure that no part of it, including the elastic, hangs over the edge of the dish, & place it in an 1100-1150 watt microwave oven, preferably one with a turntable.

‘Cooking’ this assembly for 3 minutes was shown, through very rigorous study methods, to completely sterilize the entire mask; the study authors also reported that, even if there was a small amount of metal in the mask, no sparks occurred during the process.

I want to thank Mindy R’s. husband for his question; if you have any particular topic you would like to hear more about, please message me at