A: If you're not completely gray, try highlights and lowlights; the color is painted on gray strands (to camouflage them), so the dye doesn't sit on your scalp during the coloring process. Or you could, instead, apply demipermanent color to your gray ten minutes before you apply it to the rest of your hair, says Jason Backe, Clairol's color director (demipermanent lasts longer than semi-). The extra time will allow the gray to pick up more pigment. Backe says using an ammonia-free product that contains antioxidants will prevent your hair from being damaged from the added exposure to the dye. (He, of course, recommends Clairol's Natural Instincts, $9, a demipermanent formula that should last through 28 shampoos.)
Bottom line: Your best bet is to have a professional blend away your gray with highlights and lowlights; if you color at home, you may have to use a demipermanent or semipermanent formula more often than you'd use a permanent one.