Abstract: This invention relates to an improved process for cleaning an anodized surface of aluminum or an alloy thereof where a cleaning agent is applied to the anodized surface and then the cleaning agent is removed after a sufficient period of contact,wherein the improvement comprises applying to the anodized surface at ambient temperature a thin film of a cleaning composition comprising an acid solution consisting essentially of:(a) from about 3 to 30 percent by weight, based upon the total weight of the acid solution, of nitric acid, calculated as a 65% aqueous solution;(b) from about 0.1 to 20 percent by weight, based upon the total weight of the acid solution, of partial esters of phosphoric acid;(c) from about 0.3 to 30 percent by weight, based upon the total weight of the acid solution, of a phosphonocarboxylic acid with complexing action;(d) from about 0.