If you've been using other brands of polish and wax, they may contain silicone and synthetic oils. Our car care system doesn't bond with these silicone-laden products. It's important to use Paint Prep to remove all of the old waxes, polysilicones, and oils so our care products can properly bond to the surface. Paint Prep is easy to use and is safe for vinyl and rubber. This is also the perfect prep for any painting project. Eliminates fish eyes that occur when silicone isn't cleaned from a surface before applying paint. Don't let your paint project be ruined by skipping this simple yet important step. Proper preparation is 90% of a good paint job. Paint Prep is not for use on glass. Large 35 ounce bottle includes our Finest Sprayer (a $2.99 value.)