It is best if the cup can be cleaned immediately after every use. If it is too troublesome, it should be cleaned at least once a day. You can clean it at night before going to bed and then dry it. When cleaning the cup, not only clean the mouth of the cup, but also the bottom and wall of the cup. Especially the bottom of the cup, which is not often cleaned, may precipitate a lot of bacteria and impurities. Female friends are especially reminded that lipstick not only contains chemical components, but also easily absorbs harmful substances and pathogens in the air. When drinking water, harmful substances will be brought into the body, so the lipstick remaining on the mouth of the cup must be cleaned. It is not enough to rinse the cup with water, it is best to use a brush.