Exfoliants (or abrasives) are compounds able to slough away the top layer of dead epidermis cells of the skin, thereby leaving the skin appear smoother, fresher and less wrinkled (peelings). Exfoliation can be done either mechanically with granules (shell powders) and beads, or also chemically with acids and enzymes. Surfactants cleanse and build foam by acting at the surface between fat and water (surface-active agents or surfactants). They are able of being mixed with water and fat of the skin, allowing dirt to be removed. Based on their cleansing power surfactants are classified into primary and secondary or co-surfactants.