Steps to sterilize your face mask
Pour boiling water into a bowl and add liquid soap (detergent or hand soap)
Let sit for 5 minutes. This should sterilize the fabric. You can hang to dry, but make sure mask is completely dry before wearing. You can put in the dryer with other clothes to dry as well.
I wear my mask to the grocery store and have only cleaned it once so far. Those in the medical field probably would need to clean masks each evening.
For more information, visit https://www.cdc.gov/infectioncontrol/guidelines/disinfection/sterilization/sterilizing-practices.html.