It seems no mater how much you attempt to protect your baking sheets, they always seem to end up with burn marks. A stained cookie sheet doesn't have to be thrown away, because in many cases it can be restored. You can remove cookie sheet burn marks and restore your baking implements to their former glory in a few simple steps. Best of all, you only need a few items from your pantry to do it.
Clean the baking sheet. Wash it with dish soap in warm water. Dry it completely with a hand towel. Make sure there is no grease or food debris before proceeding with stain removal.
Sprinkle the burn mark with baking soda. Do this over the sink. Pour vinegar on the baking soda. The mixture will start to foam. Use the plastic scour pad to scrub the cookie sheet stain while the mixture foams.
Rinse the mixture from the baking sheet. If the baking sheet stain is still there, repeat steps one and two until it starts to fade.
Clean burnt cookie sheets with oven cleaner if the vinegar and baking soda mixture does not work after two or three attempts. Spray the clean, dry baking sheet with oven cleaner. Let the oven cleaner set in. This should all be done outside or in a well-ventilated area because oven cleaner fumes can be dangerous.
Wait about 15 minutes before washing the oven cleaner off the stained baking sheet. Wash the baking sheet with dish soap and warm water. Make sure that all of the oven cleaner is removed before drying it.