Cosmetic clays, used in natural cosmetics and soap. Clays are great for making your own facial masks, they are typically added to shaving soap recipes to provide glide. Many people add clay to soap as a fixative for fragrance. Adding cosmetic clays to your bath bomb recipes may help to create harder bath bombs. All cosmetic clays act as gentle exfoliants, help draw impurities out of your skin, and increase circulation.