So your cleaning extruded aluminum so you can sell it as clean aluminum at a lower price, or am i missing the point? I thought yards consider aluminum clean as long as no ferrous metal is attached to it. Sounds like your yard is using the logic that a car would be considered dirty steel because the factory painted it. Ie a non metallic coating is applied to the metal. Downgrade is just a fancier way of saying dirty, just another way for the yards scam us.