You can sanitize a cloth face mask using a washing machine, but those of us using N95 masks–which are definitely better than cloth in terms of filtration–need a gentler method that won’t damage the mask.
“There are many different ways to sterilize something, but most of them will destroy the filtration or the fit of an N95 respirator,” says researcher Vishal Verma, an Environmental Engineering professor at the University of Illinois at Urbana-Champaign.
“Any sanitation method would need to decontaminate all surfaces of the respirator, but equally important is maintaining the filtration efficacy and the fit of the respirator to the face of the wearer. Otherwise, it will not offer the right protection.”
To figure out how ordinary people could do this at home without specialized equipment, Verma and fellow researcher/engineering professor Thanh “Helen” Nguyen looked at dry heating methods, as well as what people are likely to have in their kitchens. Through testing, they found that regular, domestic-grade electric cookers (like the Instant Pot) and rice cookers would do the trick in all three required areas: Decontamination, no loss of filtration, and no alteration of fit, “even after 20 cycles of decontamination.”
There are some tricks to bear in mind:
- Don’t add water
- Don’t let the mask touch the inner surface of the cooker, which would melt the mask. Use a towel as a barrier
- Run the cooker for 50 minutes
- Note that the mask needs to reach 100 Celsius (212 Fahrenheit), which means you may need to run the cooker at a higher temperature, like 170 Celsius, as you’ll see in the video below
Here’s the demo video they put together:
For multi-person households, the fact that you can stack multiple masks and do them all at once should be a welcome benefit.