To use this Crazy Color Aubergine hair dye, first do a strand and sensitivity test. Then, shampoo your hair with a pH - neutral shampoo, skip the conditioner, and towel - dry your hair. While your hair is still damp, put on gloves and apply the dye evenly. Leave it on for 15 to 30 minutes, then rinse thoroughly until the water runs clear. Remember to 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 with cold water to seal in the color. Keep your hair out of direct sunlight for too long and avoid swimming in chlorinated water. Before using any new product, do a patch test. If you experience redness or itching, stop using it.