Biff shortly after he finished waxing Marty McFly's car.
Biff's Auto Detailing was an auto-detailing company run by Biff Tannen, founded in 1980. Because Biff had to do everything for himself, and thanks to his aversion to filthy automobiles caused by twice running into a manure truck, Biff would come to the homes of his customers to wash and wax their automobiles. The business phone number, listed on the side of his Ford Courier truck, was 840-3051. Biff had also had 'Biff's Auto Detailing' matchbooks printed to give to his customers and advertise the company; he was intending to show one of these to Marty McFly when he witnessed the flying DeLorean departing for 2015.
After Marty destroyed the Grays Sports Almanac in 1955, using a matchbook taken from Biff Tannen's Pleasure Paradise Casino & Hotel in 1985A, the text on the matchbook's cover changed to 'Pleasure Paradise Casino & Hotel' to 'Auto Detailing'. In a kind of poetic justice, Marty burned the almanac using a matchbook advertising the business empire that this very book had made possible.