I wouldn't use diesel fuel, comet, or anything other than wax and rubbing compound, or just let it be. The reason being that the oil and silicones in those products will give you fits when trying to repaint the metal. The best protection to the metal would be a good coat of wax. Know that if you rub the oxidation off the paint will get thinner. I suggest you leave it alone until you paint it. If you need it to look good for a photo just wash it and take the pictures while it is wet.
