Rainbow High Fashion doll Stella Monroe. To wash your Rainbow High doll's hair 1. Undress the doll or cover the clothes with a towel to prevent the clothes from getting wet. 2. Wet your doll's hair thoroughly with water. 3. Massage in some shampoo or dish soap to remove the product or residue. 4. Optional: to make the hair even softer, you can add a little conditioner. Use your fingers to spread the conditioner over the hair or comb the conditioner through the hair. Then rinse. 5. Let the hair dry completely. 6. You can now brush and style the hair.