Self-Tanning 101 They may smell funny, but self-tanning products actually use a natural ingredient to get the job done. "Dihydroxyacetone (DHA) is a simple carbohydrate derived from sugar beets that reacts safely with your skin's proteins to produce a golden-brown color," explains Jim Hammer, a cosmetics chemist in Easton, Mass. Of course, not even the purest of products will look natural if applied clumsily. Follow these simple steps for a truly healthy tan.

BUFF Be sure to exfoliate with a scrub that's free of essential oils, says Beth Parker, an aesthetician at Smooth Synergy Spa in New York City. If there's any greasy residue on your skin, the tanner won't absorb evenly and will streak.

PREP Bare hands work better than gloves, says Susie Hatton, founder of Chocolate Sun, an organic sunless tanning salon in Santa Monica. But you'll want to stain-proof your nails with a light layer of lotion before dipping into the brown stuff.

APPLY "Go slowly and rub gently, letting the solution really soak in," Hatton says. To ensure complete coverage, wipe in one direction and then the opposite, using broad, uniform strokes. When applying to knees and elbows, which tend to look darker due to their many creases, dilute the tanner with lotion beforehand. Finally, ease up on areas that don't naturally tan, like the underside of your arms and the backs of your heels.

CLEANUP Gently rub your palms and nails, and between your fingers with a warm, wet towel to prevent staining, says Hatton.

CORRECT To tone down a tan, add a splash of skim milk to your bath--its natural acids will mellow the color, says Hatton. For random streaks or splotches, Parker recommends combining baking soda, lemon juice, and sugar, and gently buffing the paste into your skin until the problem spots blend in with the rest of your skin.

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