The wax that is used in a car wash, which forms a water-resistant coating, One of the key differences is that car-wash wax is formulated to work on glass, chrome and rubber, as well as the painted plastic and metal surfaces of the car. Waxing your car protects the paint clear coat from UV damage, and also makes the car look good. However, you can damage a paint job if you’re waxing a car that isn’t perfectly clean. You don’t want to be swirling dirt around. And it is really easy to get a less than satisfactory finish if you put too much wax on there.