Member of the Month 06/11 Happy Hoo-Ha Hacker
can I clean these cookie sheets to make them gray/silver again?
It isn't rust. The oil/fat you use to keep things from sticking builds up and causes the cookie sheets to turn brown. If they are aluminum or stainless steel and you want to put a LOT of elbow grease into them, steel wool scouring pads will take off the coating. Non-stick surfaces are a lot tougher to clean. You have to use a scouring pad that is safe for those surfaces and be careful not to ruin the finish.
Actually, the experts say that dark cookie sheets brown foods better, so if you can live with the color, it is actually best to leave the surface film and let it build up, much like seasoning a cast iron pan.
so I am just being anal about this too then (sigh)