A long time ago, I had a vet that suggested Ivory dish soap for the control of fleas. I guess the stuff smothered them and Ivory was mild enough for their skin. I will have to say that it worked. When I gave my dog (and cats - not an easy task) Ivory soap baths, the fleas would fall off dead. However, once dried, the fleas were back. But that's my input on the whole dish washing detergent thing.