The process of shedding old skin cells to allow for the new skin cells can be delayed in numerous ways. Dry skin, oily skin, even aging skin has a tough time releasing the old dead skin cells to allow the penetrating new skin to surface. Skin exfoliation helps eliminate the upper layer of skin, which is made of dead skin cells, dirt and body secretions. New skin cells are created often, and within the deepest layers of skin and can take up to 28 days to arrive to the surface.