The thing about aluminum corrosion is that once a layer of aluminum oxide forms, it seals the surface and the corrosion stops (aluminum oxide is an oxygen barrier, unlike iron oxide). Actually, once your aluminum has formed it's initial layer of oxide do NOT clean it off....that layer provides protection. Iron and steel will keep on rusting until the part eventually disintegrates...aluminum won't. All that fancy anodized aluminum REALLY is is colored aluminum oxide created under controlled conditions.