To use Rebel UV hair colour, first do a strand and sensitivity test. Then shampoo your hair with a pH - neutral shampoo, skip the conditioner, and towel - dry it. While your hair is still damp, put on gloves and apply the Crazy Color evenly over your hair. Leave it on for 15 to 30 minutes, then rinse thoroughly until the water runs clear. For maintenance, avoid dandruff or harsh shampoos as they can quickly strip the color. Use a sulfate - free or color - friendly shampoo and wash your hair as little as possible. After shampooing, rinse your hair with cold water to seal in the color. Also, stay away from too much direct sunlight and swimming, as they can fade the color. Remember to patch - test any new product before regular use. If you experience redness or itching, stop using it.