An alternative or additional method is electrolysis in an alkaline solution of sodium carbonate, with small amounts of sodium hydroxide, trisodium phosphate and borax, at a current density of about 10 A/sq.ft. The object is made the cathode, and the copious emission of hydrogen gas gives a thorough cleaning. Next, any surface oxide must be removed, or it will react with the coating to give a weak area that may separated from the substrate.