Washing them incorrectly
Disposable medical masks, N95 masks, and cloth masks can all be cleaned, but all in different ways. N95 and disposable medical masks can be steamed. But you should not apply any disinfectants to these – their chemicals cay destroy the filters in N95 masks and are toxic for you to inhale. Your cloth masks should be washed in the laundry, using your usual detergent.