For above surface contamination, using a clay bar is almost always recommended in order to achieve proper bonding of a wax. Depending on the severity or nature of paint imperfections, a cleaner/compound or polish should generally be used before a wax. Clear coat staining, brake dust, oxidation (and other contaminants that can commonly be remedied by hand use) can be removed with No. 415 Cleaner. No. 390 Prewax Auto Polish is designed for clear coat correction; removal of swirls and fine scratches. This can be achieved with a DA polisher & foam polishing pad. Moderate to medium swirls and scratches can be removed with No. 390 by substituting a microfiber pad/cutting pad on a DA polisher.