OH YEAH! I Experienced this first hand when I started my billet aluminum Banshee parts company. I "rough" polished a bunch of parts, then cleaned the buffing residue off with Simple Green. Then I final polished them, cleaned all the residue off again with Simple Green, and then sat them on my bench because I was going to wrap them up in the morning. I come into the shop in the morning, and all of my parts have this brown shit looking oxide on them. I had to rebuff every single part, and since then I only use Simple Green on stuff that I don't need to be polished. Its an excellent cleaner, its just a too alkaline for aluminum.