Dr. Shoshana Ungerleider, an internal medicine physician with Sutter Health, said on CBSN Monday that everyone should be wearing masks when they have to leave their home.
"These should ideally be washed after every use in a washing machine, if possible," she said.
Ungerleider also said people need to be careful when they remove their masks after use.
"Be really careful to not touch your eyes, or your nose, or your mouth when you're taking off your mask, and then of course, wash your hands immediately afterward," she said.
And if the mask gets worn out, it should be replaced, she said. "If you've been wearing your mask for a while and you have holes in it or it's stretched out and it's no longer covering your nose and your mouth, it needs to be thrown away," she said.
Ungerleider also cautioned that "masks alone are not particularly effective in preventing infection." The best way to prevent getting infected or prevent spreading the disease is to stay home, she said.