1. After thoroughly cleaning the car with detergents followed by a wipe-down with wax and grease remover, the work starts by sanding down the old paint with a dual-action (DA) orbital air sander. The DA sands without digging in like a rotary sander or grinder. Sanding the car down to at least the level of its original paint offers a great surface to build on if its in good shape. Heavy duct tape protects the windshield molding from getting scuffed by the sander.