Abstract: A method for enhancing the rust resistance and the surface finish of a non-ferrous workpiece, such as aluminum, is disclosed. The method comprises the step of impinging the workpiece surface for a predetermined amount of time with a high velocity stream of ferrous particles. The ferrous particles preferably have a hardness less than approximately 40 Rockwell C, preferably 20-40 Rockwell C, and still more preferably 30-40 Rockwell C. The particles are not tempered before impinging. This substantially eliminates stress cracks in the ferrous particles, thus substantially preventing any particulate ferrous matter from becoming imbedded in the impinged workpiece surface, which imbedded particulate matter may be prone to rust.