A method for removal of residue after plasma etching a film stack comprising a patterned photoresist material layer, a hard mask layer, a conductive layer, and a magnetic layer, wherein the patterned photoresist material layer and the hard mask layer form a dual mask. The method cleans a substrate containing the film stack after the dual mask of the film stack has been etched to remove residue produced during the etching process. The cleaning step is performed in a solution comprising hydrogen peroxide and ammonium hydroxide that removes the residue.