Microdermabrasion
Microdermabrasion is 
essentially powerful mechanical exfoliation with an expensive machine, generally either the original crystal microdermabrasion technology or the newer diamond-tip microdermabrasion. Both work by removing the uppermost layer of dead skin cells from the face, chest and hands. True microdermabrasion is usually done in a day spa,medical spa or specialized skin care studio. It gives results you can’t achieve with a home microdermabrasion kit, which is basically a scrub for the face that is often too abrasive and can even irritate skin. How long does a microdermabrasion treatment last? The actual microdermabrasion procedure is quick — it takes just 15 to 30 minutes. This doesn’t include the cleansing of the face prior to and after the procedure. How many treatments will I need? While your skin will feel smoother after just one treatment, you really need a series of treatments to see any positive effects. The results are cumulative. Generally, six to 10 treatments are scheduled 7 to 14 days apart. The number and frequency of treatments varies depending on your skin’s needs and your skin care goals. What does microdermabrasion feel like? Does it hurt? Some people liken it to the rough lick of a cat’s tongue. Others describe it as a gritty facial massage, or report feeling just minor tugging on the skin. However it’s described, you needn’t worry. Because it works on just the surface layers of the skin, microdermabrasion isn’t painful. What can I expect after the treatment? After a microdermabrasion treatment, your skin will be a bit pink. This usually fades within a few hours.. How Microdermabrasion Works? The crystal microdermabrasion device consists of a compressor that draws in air through a hand-held wand. When the wand touches the skin, a vacuum is created. Aluminum oxide crystals, also known as corundum (the second-hardest mineral next to diamonds) blast across the skin’s surface, picking up dead surface skin cells along the way. The crystals and dead skin cells are quickly sucked up through a different tube in the same wand and go to a disposal bag. The depth of exfoliation is controlled by the strength of the vacuum and crystal flow, which is determined by esthetician. He or she makes two passes over your skin, sometimes a third if your skin is thick enough or if there is an area that needs special attention, like a scar or brown spot.
Source: http://spas.about.com/od/medicalspatreatments/a/microderm.htm