Don't try to clean and reuse an N95 mask. We found that out the hard way when we had to correct our initial advice. But you can clean and reuse a cloth face covering.
Correction, April 10: Since this story originally published on April 8, one of the experts we cited has changed his recommendations. We've changed our story to reflect that and we've looked to additional sources of information for deeper perspective. We'll continue to update with new information.
There is intense interest around ways to disinfect and reuse an N95 mask, but if you're looking for that advice you're probably barking up the wrong tree. N95 facepiece respirators are "not approved for routine decontamination and reuse," according to the Centers for Disease Control and Prevention. While many efforts to do so are making headlines, and may read like household advice, those innovations are intended for professional settings and equipment.
Wear a cloth face mask or covering as recommended by the CDC -- it's not some shabby ineffective option. "It's preventing particles that come out when you cough from going out into the general public. In that situation, a cloth mask is as efficient as any medical grade mask," says Margaret Gardel, technical spokesperson for N95DECON, a collective of scientists, engineers and clinicians from 10 major US research universities that reviews and disseminates scientific information about N95 decontamination. "The general public should not be wearing disposable surgical masks or N95 masks out in public."
"If cloth masks are worn universally by the general public, this will dramatically reduce asymptomatic spread of the virus as well as provide adequate protection against virus inhalation," says Gardel. "The risk of cross-contaminating yourself by using a mask that cannot be decontaminated well is greater than if you use a cloth mask, in my opinion."
Effective cloth face coverings are easy to make and don't require specialized material like an N95 does. "Although viruses are small they are spread by larger droplets that are too large to fly through the small holes in a tightly woven cloth mask," says Dr. Daniel Griffin of the Department of Biochemistry and Molecular Biophysics at Columbia University.
Unlike an N95 mask, which requires complex, industrial methods of disinfection, a cloth face covering is readily disinfected by standard machine washing. "The reason it's so hard to disinfect an N95 mask is because it's meant to be disposable," says Gardel. "But a cloth mask you can just stick in the laundry with soapy water under high heat and it's perfectly safe when it comes out of the dryer."
We learned that none of them are adaptable for home use, though they may sound like it.
Mask cleaning efforts include saturation with hydrogen peroxide vapor, steaming at 257 degrees Fahrenheit, dry heat applied via an institutional oven and rotating a mask out of use for at least 72 hours, based on the belief that the coronavirus can't survive longer than that on an inhospitable surface. Some of these methods have become accepted, others not yet, but all of them are designed for institutional settings.
In spite of uniform advice that N95 masks are inappropriate for use by the general public, we know that many of them are in households. If you insist on using them in public rather than donating your N95s to front-line workers, at least know how to properly put one on and take it off. Don't let your hands create a bridge between the particle-trapping front of the mask and the ostensibly clean back of it. Practice these CDC N95 steps
to don and doff your mask properly.
The appetite to use "professional" gear is understandable at a time like this, and the often whimsical nature of DIY cloth face coverings may make them seem trivial, but they do the job needed and are easily disinfected.