$ 0 0 Elevate in a covered dish above (not in) ~2 oz of water (no dry heat).[1]Microwave to a boil. (Over 133 degrees F is really all that's needed.[2])Let it sit a minute or so. Take it out and let air dry.1. https://www.cdc.gov/coronavirus/2019-ncov/hcp/ppe-strategy/decontamination-reuse-respirators.html2. https://www.who.int/csr/sars/survival_2003_05_04/en/