A process and bath for electropolishing and brightening aluminum and aluminum alloys. The bath preferably contains from about 30 percent to about 95 percent phosphoric acid and from about five percent to about 70 percent of a poly (alkylene ether). A minor amount, generally from about 0.05 to about two percent, of a wetting agent may be added to the bath if desired. The bath forms a protective foamy film over the part being electroplated, thereby protecting the part against chemical attack by the bath. Further, the polyether additives are chemically and thermally stable in the electrolyte under normal bath operating conditions. The bath may be operated at low voltages ranging from about 15 to 100 volts.