The outer layer of the mask often accumulates a lot of dirt, bacteria and other dirt in the outside air, and the inner layer blocks the exhaled bacteria and saliva, so that the two sides can not be used alternately, otherwise the contaminated dirt will be directly Face when inhaled the body, and become a source of infection. When the mask is not worn, it should be folded into a clean envelope, and will be close to the nose and mouth side of the fold, do not just stuffed into the pocket or hanging in the neck.

If the mask is exhaled hot air or saliva wet, the role of blocking the bacteria will be greatly reduced. So, usually the best time to prepare a few masks, in order to replace the use, should be washed once a day. Wash should be used for 4 minutes before boiling water.