Boiling, Steaming, Heating, Rotating: Orange County Doctor Researches How to Reuse N95 Masks

The doctor's four cleaning and reuse methods are detailed in an article for the Journal of Emergency Medicine.

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The shortage of personal protective equipment — specifically those N95 masks — continues to be a struggle for many healthcare workers. But an emergency medicine doctor in Orange County, California, started researching solutions and found inexpensive ways to clean and reuse them.

Billions of N95 masks are needed to protect U.S. healthcare workers during the pandemic, but production cannot yet meet the demand, which leaves those on the front lines struggling for solutions. 

"I would hear things on the emergency medicine blogs on how they would use soap and water or spray with Lysol or use hand sanitizer, and that just wasn't a recommended or effective way, so I started searching for a solution," Dr. Pascal Juang said. 

The emergency medicine physician based in Orange County reached out to retired University of Tennessee engineer Peter Tsai — who invented the mask's virus blocking technology — to brainstorm ways to clean and reuse them. 

"The masks are made out of PPE plastic with an electric charge embedded in it, so it acts like a strainer with a magnet in it to trap particles," Juang said. 

The masks are designed to trap particles, including the airborne novel coronavirus, but they're supposed to be used only once. Machines with hydrogen peroxide vapor now have emergency use authorization by the FDA to sterilize N95s, but the systems are expensive and not yet widely available.

So Juang and Tsai detailed four emergency sanitizing methods in their article for the Journal of Emergency Medicine: boiling, steaming, heating and rotating.  

Juang says a lot of these methods can be done in the hospital "with little or no cost."

"There are actually blanket warmers that are available in most hospitals that go up to 158 degrees Fahrenheit and these masks can actually be hung," he said.

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N95 DECON USING A BLANKET WARMER FOR 60 MINUTES PROOF OF CONCEPT: This is a picture of a blanket warmer commonly available in many US hospitals. The virus on masks can be killed using these blanket warmers. The cleaning methods discussed in my Journal of Emergency Medicine article can be deployed immediately, anywhere around the world at little or no cost. • • • Please see references below: • • “N95 Respirator Cleaning and Reuse Methods Proposed by the Inventor of the N95 Mask Material”. Juang P, Tsai P. Journal of Emergency Medicine, April 2020. • • To find the online link to this article – Google search: “Pascal Juang N95 Mask”. It is a “pre-print” PDF. That means it will undergo a final edit before printing. • • • Rotating a mask every three days, heating, boiling or steaming the mask. There is scientific evidence supporting complete viral killing after 60 minutes of heating at 70°C, (158°F). The NIH released a study yesterday confirming SARS-CoV-2 (the name of the virus that causes COVID19) is neutralized using dry heat for 60 minutes. Previous studies indicated 30 minutes was sufficient. THIS CAN BE DONE 2 TIMES TO EACH MASK. After two cycles, mask degradation was noted by the NIH. However, this is more likely from physical wear and tear on the mask due to reuse. The inventor of the mask material heated N95 masks at 70°C for 24 hours without a decrease in the filtering efficiency of the mask material. A similar set up with a wooden dowel (Chop sticks, etc) can be used to hang masks in boiling water, keeping most of the elastic band out of the water. • • For details and references – see previous post (March 28) on N95 mask cleaning and reuse. PLEASE REPOST AND SHARE -so people can learn more and understand what to do: Social Distance, Wash Your Hands and Don’t Touch Your Face! It’s the greatest weapon that nonmedical people have to help us fight COVID19!!! Stay Safe Everyone! #n95decon #health #wellness #medicine #socialdistancing #handwashing #emergencymedicine #firstresponderslive

A post shared by Pascal Juang, M.D. ( on

One hack demonstrated above on Juang's Instagram page involves using a simple dowel as a rod to transform the blanket warmer. But masks can only be heated twice before degrading. So perhaps the simplest solution is rotating masks.

"After three days on plastic, all virus dies, so you can actually reasonably rotate these masks every three days, but you have to have three masks," he said.


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Note that it is not necessary to rotate your masks unless you have an N95, which really should only be used in healthcare settings.

For cloth masks which most of us are wearing the safest bet is to wash it with soap and water at the end of every day.

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