A shaped elongate strap enables a plastic grocery bag to be used for trash disposal in a vehicle. It has a shaped headrest post gripping top portion at one end and a shaped grocery bag handle gripping portion at the other. The top portion encircles both headrest posts, allowing the strap to drape over the shoulder of the seat so that the bag gripping portion hangs between the seats. The bag gripping portion comprises two spaced-apart hook parts for the bag handles.