You probably have oxidation. You don’t usually see oxidation, but the dulling of your paint’s finish is a sign of oxidation. Oxidation is caused by the weathering of the painted surface on your car, primarily from the intensity of the sun’s rays as well as exposure to moisture. The natural oils are lost because the sun dries out the top layers of paint. If these oils aren’t replaced, the paint oxidizes. Your car’s color slowly changes due to oxidation, stripping your car of the shine that it once had when it left the showroom. The surfaces that are most affected are the flat surfaces, such as the hood, roof and trunk of the car because of exposure to direct sunlight. Oxidized paint is also described as “dead paint.”