there are different kinds of masks for different purposes, some are deep cleansing for cleaning the pores. effect can be revitalize, rejuvenating or refreshing. facial masks are most commonly used by women but also used by men. some masks are washed off with tepid water, others are peeled off by hand. duration for wearing a mask depends on type of mask, but can be 3 minutes to 30 minutes, and sometimes including the whole night.