Abstract: There is disclosed a method for surface treating aluminum products, especially vehicle wheels, to improve their brightness. The method comprises: (a) applying a chemical brightening composition to these products; (b) deoxidizing the surface of these wheel products in a nitric acid-based bath; (c) forming a porous oxide on that with an electrolytic bath containing phosphoric acid; and (d) applying, preferably spraying, a siloxane-based film to that porous oxide. In many instances, intermediate rinsing substeps are performed between these respective main steps.