MINERAL MAINTAINENCE: Achieves the best results from your Colorescience brush. Clean your brush after each use if your skin is being treated or has a skin disorder. Clean as needed if you have healthy skin. This unique brush cleaner contains minerals that are housed in a concealed compartment, seperated by a sanitary filter, which keep the minerals free of contamination, making it the ideal choice for acne and sensitive skin. The bristals are 100% pashmina, to softly blend and buff the minerals on to the face.