Since it's a temporary color you can also try a good clarifying shampoo, it's made to remove all types of chemicals out of the hair. but just use a very good conditioner after it. I never heard of using dawn but who knows it just may work ok. Even with a semi-permanent color be careful of the choice for the blond section. It will have a tendancy of "grabbing" the color faster so watch your timing and check it often by wiping some color off a small piece and look at it. if its not enough put a little more on and watch again. You probably won't need the full amount of time. Good luck