Highly recommended, yes. Any scratch, swirl or blemish existing on the paint that is then coated, becomes locked in and will remain visible and protected. It is advisable to sand out heavy scratches, polish out light scratches and then polish out light swirls with our Puris compounds and Puris polishes using a rotary or dual action machine for a flawless finish, then wipe clean with alcohol to ensure a grease free, dust free surface. Then apply the Jade ceramics.