Vacuum all seating areas, getting inside the gaps and cracks of the seats as much as possible. A hand held vacuum works well and if you intend to use a household vacuum for this, a narrow crevice tool hose attachment is best for getting into those cracks and crevices. Most self-service car washes have vacuums on the premises you can use for a small fee. Be sure to move the seats to the farthest back position and check the floor for loose items, pens, change, etc., and then vacuum under, around and behind the seats. Don’t forget to vacuum out consoles, door/map pockets, storage bins and ashtrays.