When wearing and taking off the mask, make sure your hands are clean. If you plan to reuse the mask, store it in a dry, clean ventilated place or keep it in a clean, breathable paper bag. Masks need to be stored separately to avoid contact with other people’s masks. During the pneumonia epidemic of novel coronavirus infection, masks are more scarce and their use can be extended for a longer period and more often if they are worn and stored correctly. If the mask is dirty, damaged or smelly, which causes breathing difficulties, it needs to be replaced in time.