The California Department of Health suggests cleaning your face mask in your washing machine as you would your clothes.

According to the CDC, you should wear a mask in public, particularly while in “settings where other social distancing measures are difficult to maintain (e.g., grocery stores and pharmacies)” and “especially in areas of significant community-based transmission.” Think of circumstances where it’s going to be harder to keep at least 6 feet away from other people, especially in closed, poorly ventilated places. It’s in those kinds of situations that coronavirus-containing droplets are more likely to spread by air or surfaces.

The CDC offers some tips for how to properly use a mask. Above all, don’t touch the mask and then touch other parts of your face, especially your eyes, mouth, and nose. The entire point of this fabric is to shield you from outside germs. So you don’t want to touch the part of the mask doing the shielding and then the parts of your face that are vulnerable to infection. You should also wash your hands before and after taking off a mask — before to avoid getting anything on your face and mask, and after to get rid of anything that was on your mask. Remove the mask with the loops, not by touching the front.

The CDC recommends a cloth mask or face covering, whether a professionally made mask or a homemade variant. The CDC explicitly advises against the general public using a surgical mask, which is the standard mask you’ve probably seen doctors and nurses wear. It also advises against the public using N95 respirators, which are more complex, expensive masks meant to fit more tightly on the face. Surgical masks and N95 respirators, the agency noted, “are critical supplies that must continue to be reserved for healthcare workers and other medical first responders, as recommended by current CDC guidance.”

The CDC’s guidance — and the best argument for wearing a mask, according to the experts I spoke with — is primarily to stop the wearer from infecting other people. That’s especially important for Covid-19, since at least some spread happens when people are asymptomatic, when they have few symptoms, or before they develop symptoms. Universal mask use could stop these asymptomatic carriers, many of whom might not even know they’re sick, from inadvertently infecting other people. Masks also can offer some protection from others by putting a physical barrier between them and your mouth and nose. But we don’t know how much, because it’s unclear how much the virus spreads through airborne droplets or aerosols.