Can gasoline kill scabbies?

That's going nuclear. Because scabies lives under the skin (not on top like head lice or pubic lice) gasoline would have to soak through the skin in order to kill the scabies "mite". Aside from being flammable and having toxic fumes, the gasoline will probably kill a lot of healthy skin cells as it tries to kill the mite. Try a milder approach such as Elimite (permethrin) cream from the doctor, instead of going nuclear on the mite.