Abstract: An electrochemical method for selective removal of the metallic residual stain which forms on molybdenum masks during processing of integrated circuits. The method forms an electrolytic cell which has, as its elements, the mask as the anode, an electrolyte of phosphoric acid and glycerol, a cathode, and a power supply. That cell is used to electrochemically clean the mask, forming a surface film and electrolyte layer on the mask which includes the metallic residual stain. To remove the surface film and electrolyte layer and, concurrently, the metallic residual stain, the mask is rinsed with water. It is then dried.