How to make your own and Use Cloth Face Coverings to Help Slow Spread | CDC

Cloth face coverings should— fit snugly but comfortably against the side of the face
-- be secured with ties or ear loops
--include multiple layers of fabric
-- allow for breathing without restriction
-- be able to be laundered and machine dried without damage or change to shape

https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/diy-cloth-face-coverings.html