The dry heat of electric cookers is an effective sanitization tool for delicate masks, according to a new study published in the journal Environmental Science and Technology Letters. Researchers found N95s were successfully decontaminated after 50 minutes in an electric cooker. Even after 20 cycles, masks were still in good enough shape to to continue to filter at their full capacity (up to 95% of fine particles) and fit properly.
An Instant Pot seems like an unusual tool to use to decontaminate a mask, but study author Nguyen Thanh Nguyen, PhD, tells Verywell that it was important to use something that’s accessible to many people.
“[Families] cook at home almost every day using a rice cooker or Instant Pot,” she says.
In the study, Nguyen and her co-author Vishal Verma, PhD, both professors of civil and environmental engineering at the University of Illinois, Urbana-Champaign, took four different viruses—including a coronavirus—and applied them to different locations on an N95 mask, including the inside edge, the inside center, the outside edge, the outside center, and the strap. They then put each mask inside a Farberware electric cooker purchased from Walmart, and turned the machine on for 50 minutes.
The conclusion, according to the researchers: Using an electric cooker “is an appropriate decontamination technology for N95 respirator reuse.”
The Farberware cooker they used is similar to the popular Instant Pot. Both work by creating heat under a tight seal.
N95 Respirators Require Special Care
N95 masks are made of a mix of polyester and polyurethane, and they also contain an electrostatic charge to help capture airborne particles, Verma tells Verywell. Because these are designed for one-time use, the concept of cleaning them is fairly new—and challenging.
“If you wet the surface of the mask, that electrostatic charge will be gone,” Verma says, explaining the mask has to be cleaned with dry heat instead. “A washing machine will not work. It will degrade the performance of the N95 mask, for sure.”
How an Electric Cooker Can Decontaminate a Mask
One cooking cycle of an electric cooker, like an Instant Pot or rice cooker, can maintain a temperature of 212 °F. When a mask is exposed to that level of heat for 50 minutes, it will kill viruses—including SARS-CoV-2—more effectively than ultraviolet light, the researchers found.
To decontaminate a mask using an electric cooker:
Use a small towel to line the interior surface of the pot. This prevents the surface of the cooker from burning the mask when it heats up. It’s possible to decontaminate several respirators at once if your cooker is large enough. Don’t put anything else inside the machine, including water; it will lessen the effectiveness of the process and the mask’s ability to work afterward. Set the cooker to 50 minutes. When the 50-minute cycle is done, the respirators are ready to be used.
Verma and Nguyen created a YouTube video to help demonstrate exactly how people can try this at home.
While Verma and Nguyen designed their experiment to try to help healthcare workers extend the life of their N95 masks, not everyone is convinced this is a good idea.
“This type of disinfection is not likely usable for healthcare workers at the present time as it is not an endorsed method by the FDA or the CDC,” Aline M. Holmes, DNP, RN, a clinical associate professor at the Rutgers University School of Nursing, tells Verywell. Instead, she recommends healthcare professionals consider the use of aerosolized hydrogen peroxide as an effective treatment.
What About Cloth Face Masks?
N95 masks are difficult to find right now, and the CDC specifically states that N95 respirators should be reserved for healthcare workers and other first responders due to shortages. The general public should use cloth masks or bandanas. However, Nguyen says this method may be helpful for people who have N95 masks at home from pre-pandemic times and want to reuse them.
It’s not clear at this time whether an electric cooker could work on a cloth mask, given that the researchers didn’t test them. While Ngyugen points out that most cloth face masks can be washed with soap and water in the washing machine, she also says that the electric cooker treatment “will inactivate pathogens, regardless of what mask you’re using.”
But Isabel Valdez, MPAS, PA-C, CPAAPA, an internal medicine instructor at the Baylor College of Medicine, tells Verywell that high levels of heat have the potential to make cloth face masks less effective.
“Depending on the fabric or filters used in your cloth mask, the high heat could degrade the materials making them obsolete,” she says. “Washing according the recommendations for the type of fabric used is more than enough to achieve the level of decontamination needed by the general public.”
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medRxiv 2020.03.24.20041087. doi:10.1101/2020.03.24.20041087
