Fun fact: In the novel 101 Dalmatians, to disguise themselves from Cruella, Pongo, Mrs. Pongo (her name was NOT Perdita, that was a different female dog that helped nurse the pups), and all the puppies rolled in ashes so they looked like pure black dogs.
When they got back to the Darling's home, the humans almost ignored them because they didn't look like dalmatians...until they noticed the soot rubbing off.
So this is ALMOST plausible. lol