I am a vet and I will tell anyone on this site that DAWN AND PERT PLUS KILL FLEAS!!!!!! However after using either of these products just be sure to use a good dog or cat conditioner...
I'll eat my hat if you are really a vet. I find it incredulous that a vet would join a forum, and in their first post announce they are a vet and recommend a product or three.
I am NOT a vet and would recomend anyone get advantage before suffering numerous bites and scratches attempting YOUR "cure"(which BTW is VERY temporary. Enough water will wash away fleas with no soap needed).
I did use Dawn on one of my cats who was an orphaned kitten. I used it when he was still too young for the Frontline. It is temporary but he was badly infested and the fleas had to come off or he would've died from anemia. As soon as he was old enough and strong enough I gave him a dose of Frontline.