no need to wash it off , you can't once it dries it bonds to the hair fibers and lasts several washingsTreatments for mange, scabies, or other mites will often be based on permethrin.
Gordon's Permethrin 10, diluted 20:1 will give a .5% solution.
Wet the dogs with the .5% solution (dip or spray), give it several hours (or over night) to work, then give them a bath to wash it off.
eta: You might want to treat them again in about a week, in case any mites or eggs were missed.
Wow! Sorry for your situation.Lol I meant collies not cookies! Ivermec is often advised but not for this breed.
I bathed with a pyrithrin shampoo yesterday. Since both dogs and myself are infected have to think it's sarcoptic.
Has anyone tried happy jack sarcoptic mange medicine? It's sulfur based and natural and says guaranteed.Both dogs slept the day and I was hopeful. When night came the younger one had a terrible reaction
She was running around whining and fussing all night. When morning came her tail was all red and bloody. I don't know whether the spray was at fault or it got the mites active?
This is so discouraging!