Bleaching hair that you have already dyed brown can be more complicated than bleaching your natural hair colour. Using a harsh chemical like bleach to lighten your hair can damage it, and applying bleach over hair that has already been chemically treated will only add to that risk. Still, bleach is a straightforward way of removing the colour from your hair if you get tired of your brown hair and want to dye over it, or if you simply want to lighten the colour.
Prepare the bleach solution in the hair removal kit according to package directions. Wear the latex gloves to protect your hands.
Divide your hair into several sections and pin up all but one of the sections so they're out of the way. Using the applicator brush provided with the kit, apply the bleach mixture to one section of hair from the root to the ends. Lift the hair to apply bleach evenly to both sides, and pin it out of the way when you're done.
Unpin the next section of hair and apply bleach mixture to the top and underside of the hair as before, working from the root to the ends. Repeat the procedure with remaining sections of hair.
Cover your hair with the shower cap to prevent a mess or accidental contact with the bleach. Let the bleach sit on your hair for 40 minutes. Check the colour. If your hair is white, the bleach is ready to come off. If not, let it sit for another 10 minutes.
Rinse the bleach out with warm water. After rinsing, wash your hair with shampoo and conditioner.
Hair bleaching may take longer on hair that has already been dyed. Bleach lightens artificial pigments more slowly than natural pigments.
Be gentle with your hair after bleaching it. Keep it hydrated and use only mild products on it before and after the bleaching process. If you plan to dye your hair again, wait a few days after applying bleach to reduce the possible damage to your hair.