Oh My Gluestick: Homemade DOG SCRUB flea treatment shampoo. DIY flea killer for pets: mix half a container of iodized salt & a few squirts of the blue Dawn dish soap to get the consistency of a good salt scrub. dont want it too runny or dry. Scrub pets, rinse, careful not to get in eyes. Dawn is the source of killing fleas. Massaging salt in the skin helps to kill flea eggs that were laid.