When treating for scabies, do i have to disinfect my car? how would i do that? how about couches?

No! : Vacuum. Wash bedclothes in hot water and dry in a dryer. If you want to be really careful, place recently worn clothes in a garbage bag for 3days, then wash. The main thing is to get treated with a scabicide cream and have the people who have had prolonged direct contact with you treated. Scabies mites do not survive more than a couple of days off human skin.