Cloth masks should be washed in hot water, not hand washed.
...handwashing doesn't provide adequate protection. Instead, cloth masks need to be washed at high temperatures.
The healthcare workers who self-washed their masks by hand had double the risk of infection compared to those who used the hospital laundry.
"The WHO recommends machine washing masks with hot water at 60C and laundry detergent, and the results of our analysis support this recommendation," Prof MacIntyre said. "if a cloth mask was washed in the hospital laundry - "they were as effective as a surgical mask"."
But hospital laundries use extra hot water, special detergents, and bleach. It sounds as if one should use a "sanitize" cycle with bleach, or at least the hottest water your machine can do with bleach. Some households keep their hot water heater set to a low setting to reduce their carbon footprint. This may be a problem for killing covid.