In response to questions about using household microwave ovens to clean face masks to kill coronavirus, the Association of Home Appliance Manufacturers (AHAM) offers the following statement:
Microwave ovens should be used only as intended to thaw, cook and reheat food and beverages as described in the use and care manual that accompanies each unit. AHAM does not recommend using household microwave ovens to sanitize face masks. AHAM does not have any research to support claims that household microwave ovens are effective at sanitizing face masks.
Further, there is a concern that microwave ovens could degrade the cloth fibers and plastics in face masks. Some masks also contain staples or metal to secure straps. It is hazardous to put metal in the microwave, as it can cause arcing or sparks.
For information on how to clean your face mask and other tips, please consult the following link provided by the CDC. https://www.cdc.gov/coronavirus/2019-ncov/downloads/DIY-cloth-face-covering-instructions.pdf