We used to clean up sets quite a bit - a damp rag, some spray cleaner and a little elbow grease went a long way. We figured the customers hadn't seen their set in a few days, and getting back a dirty set they brought in could reflect badly on us, so we always gave them a going over.
Problem was, we cleaned one 12" Sharp Black and White set a bit too well - all the tar and cigarette crap had turned the set a dull yellow. Once cleaned up, she was back to a white cabinet. The guy picks up the set, takes it home, and the wife complains about the "
wrong set", "
scheming shop", and "
take it back and get ours" - so he brings it back around 6:30 the same evening, telling me that he got the wrong set. I pulled the service manual, showed him the model was only available in white, and pulled the back off to show what the discolored/dirty plastic inside looked like. I told him how we cleaned the cabinet and got it back to the lovely white it was when he bought it. His troubles had doubled then - he couldn't take the set home to tell his wife it was dirty while sitting in her kitchen.....