Processes for cleaning anodic film pore structures are described. The processes employ methods for gas generation within the pores to flush out contamination within the anodic film. The pore cleaning processes can eliminate cosmetic defects related to anodic pore contamination during the manufacturing process. For example, an anodic film that is adjacent to a polymer piece can experience contamination originating from a gap between the anodic film and polymer piece, which can inhibit colorant uptake of the anodic film in areas proximate the polymer piece. In some cases, an alternating current anodizing process or a separate operation of cathodic polarization is implemented to generate hydrogen gas that bubbles out of the pores, forcing the contaminates out of the anodic film.