Your class-cutting, curfew-missing, car key-begging teen has turned your hair gray. You've dyed it a few too many times (to try to recapture your "natural" color) and now it's beyond brittle and fried. Try a grapefruit-infused shampoo. Citrus oil, particularly grapefruit, is known to soften and shine hair. It's a cheap way to get back that youthful glow (without the acne!).