Self serve carwashes...… Who knows what gets washed off or sucked up there. Lots of things cleaned there that would not be cleaned at home.
Buddy had a late 60's Chevy wagon and was bar hopping with another buddy who had already well exceeded his limit and was semi passed out on the back seat. As the car rounded a curve, chocking, gagging and retching sounds came from the back seat as dinner and a dozen shots and beers poured forth all over the rear interior.
Fortunately, a car wash was nearby and the driver, gagging himself at this point, managed to roll into a vacant bay. He opened the door and wanded down the retcher as well as the vinyl interior and then proceeded to the vacuum where he sucked up water and food particles. Canister must have smelled great when emptied. The retcher was driven home and the car left to vent and dry overnight on a 0 degree night. That seat and floor had ice until Spring and stunk until he totaled it
