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How to Disinfect Your Cloth Mask

May 19, 2020

How to Disinfect Your Cloth Mask

Need to protect your employees but want to give their masks a bit of character? The/Studio is a responsibly-sourced, verified seller of custom, anti-bacterial trifold cotton masks to international companies, family businesses, military groups and individuals. Place your order here.


By Nidiane Martinelli, PhD

Somehow, it has become “normal” to go out wearing masks at all times worldwide — and for good reason. We do it to go to the grocery store, take a walk, or encounter some friends while still practicing social distance — and drastically inhibit the spread of COVID19 and other contagious diseases.

In many parts of the country, the new normal is to wear a mask, period. So, what is the appropriate way to really clean the masks after going out? Or to disinfect it? Many of our customers have asked since they’ve begun to switch from disposable masks to store-bought (or homemade) reusable ones.

Before we dive into it, it is essential to remember that masks reduce virus transmission from the mask-wearer and virus inhalation by the mask-wearer. So, it is a virtuous cycle that’s reliant on not only cleaning but regular cleaning — think daily. And last but not least, for protection, masks must cover the nose and mouth. 

There are many protocols on how to clean and disinfect N95-type masks; however, there are no such protocols for cloth masks. The studies for the disinfection of N95s are based on SARS-CoV-2 or virus quantity reduction or inactivation measurements, so one could wonder that it can also be used for cloth masks.

There is evidence supporting heat inactivation of viruses like SARS-CoV-2, Influenza H1N1, and Influenza H5N1 on N95 respirators. One study showed that by microwaving the respirators for 2 minutes in a container was sufficient to deactivate Influenza H1N1, considering a 1250 W microwave power. A similar result was obtained when respirators contaminated with Influenza H5N1 were microwaved for 1.5 minutes in a steam bag (1100 W microwave power). 

Specifically, for the SARS-CoV-2, there is no study using a microwave to disinfect masks. But there is one study that showed SARS-CoV-2 inactivation with dry heat. This study literally baked the N95 respirators inside an oven for 60 minutes at 70°C or 158°F and got acceptable disinfection results.

But thinking about what people have at home, washing your cloth masks with soap and water is already pretty efficient. If you want to go above and beyond and try to disinfect them, you could try the microwave or conventional oven methods— but first, always wash the cloth mask with soap and water.

And remember to stay safe and be kind during these challenging times. 

Bear in mind that those are just suggestions and were not tested on cloth masks. Those were tested for N95 respirators, and those conditions were efficient. Up to date, I have no knowledge of studies evaluating the effectiveness of heat to inactivate SARS-CoV-2 on cloth masks. Thus, the content here is for informational purposes only and does not constitute the providing of medical advice; it does not intend to be a substitute for independent professional medical judgment, counseling, diagnosis, or treatment. Use it or reliance upon it is solely at your own risk.


Need to protect your employees but want to give their masks a bit of character? The/Studio is a responsibly-sourced, verified seller of custom, anti-bacterial trifold cotton masks to international companies, family businesses, military groups and individuals. Place your order here.

References: 

Technical Report for Heat-Humidity-Based N95 Reuse Risk Management. https://static1.squarespace.com/static/5e8126f89327941b9453eeef/t/5ea25d8b4965f32f414d974c/1587699083786/2020-04-23_N95DECON_Heat_Technical_Report_v2.0_final.pdf accessed on May, 18th, 2020.

Decontamination and Reuse of Filtering Facepiece Respirators. https://www.cdc.gov/coronavirus/2019-ncov/hcp/ppe-strategy/decontamination-reuse-respirators.html accessed on May, 18th, 2020.

https://www.n95decon.org/resources accessed on May, 18th, 2020.

R. Fischer, et al. Assessment of N95 respirator decontamination and re-use for SARS-CoV-2 medRxiv 2020.04.11.20062018; doi: https://doi.org/10.1101/2020.04.11.20062018

Anderegg, L.,et al. (2020). A Scalable Method of Applying Heat and Humidity for Decontamination of N95 Respirators During the COVID-19Crisis.​medRxiv.A​ dvanceonlinepublication. https://doi.org/10.1101/2020.04.09.20059758

Kumar, A., et al. (2020). N95 Mask Decontamination using Standard Hospital Sterilization Technologies. ​medRxiv.​ Advance online publication. https://doi.org/10.1101/2020.04.05.20049346

Technical Document for Public Use of Medical Masks and Cloth Masks. https://static1.squarespace.com/static/5e8126f89327941b9453eeef/t/5ea3b5859bc8f31a11f3deb5/1587787141808/2020-04-24_N95DECON_Face_Mask_Technical_Report_v1_final.pdf accessed on May, 18th, 2020.

Decontamination Methods for 3M Filtering Facepiece Respirators such as N95 Respirators. https://multimedia.3m.com/mws/media/1824869O/decontamination-methods-for-3m-filtering-facepiece-respirators-technical-bulletin.pdf accessed on May, 18th, 2020.