In order to swap eyeshadow colors between uses gently swipe the brush back and forth over the sponge a few times. The scrubbing sponge will remove pigment from your brushes quickly. Both sides of the black sponge are usable simply flip the sponge and use both sides before cleaning. The reusable sponge is very easy to clean, just run under warm water with a bit of soap and allow to dry. Clean at least once a week.