Exfoliation is the natural process that all skin goes through- the outermost layer of the skin are sloughed off and replaced by the new cells that move to the surface.
This endless inside-to outside outside movement is the hallmark of healthy skin. For many reasons this healthy cell turnover process can be impaired, causing problems for many skin types. An excess of surface skin cells that don’t shed normally can be the result of sun damage (sun damage causes the surface layer of skin to become thick and scaly, while it thins and depletes the support structures in the layers below the surface). It also can be caused by oily skin preventing natural exfoliation because the excess oil makes skin cells stick to the surface.
Overly emollient skin-care products that basically hold skin cells down can do the same thing. For some skin disorders, and as a result of sun damage, abnormally generated skin cells adhere unevenly and tenaciously to the surface of skin, another problem that slows healthy exfoliation. What happens when we help the outer layer of skin function more normally? Your face can truly look younger! The best analogy I can think of is to compare it to the heels of your feet. Before you get a pedicure, the built-up, dead layers of skin on your heels look dry rough, discolored, and scaly, and there are pronounced lines. Once that layer is removed, and it can be removed fairly aggressively without damaging anything, your heels look much better.
Moreover, once you apply moisturizer, which can now be absorbed better because it isn’t being blocked by the presence of overproduced skin cells, Voila! You have “younger”-looking feet. The wrinkles are gone, the thick scaly appearance is gone, the dryness is gone, and your heels look beautiful. I’m not suggesting we should be that aggressive from the neck up or on most parts of the body but the same benefits you gain when exfoliating skin on your feet hold true for the face. You just have to be more gentle than you are with your heels!
Topical scrubs are one way to exfoliate, which can be as simple as using a washcloth, or a cosmetic cleanser that contains a gentle (not gritty or skin damaging) abrasive material. However, research has solidly established that salicylic acid (BHA), for normal to oily or blemish-prone skin, and alpha hydroxy acids (AI-lAs) or polyhydroxy acid (PHA), for normal to dry skin, are not only effective exfoliants but also increase collagen production, improve a the overall health of the skin, increase cell turnover, and reduce the appearance of skin discolorations. Therefore, those types of exfoliants are preferred to scrubs because they deliver greater, multi-faceted results.