I know a lot of knifemakers use stainless foil to wrap the blades when they are hardening them. Keeps them from being exposed to oxygen when they are hot which will decarburize the surface of the steel (and just make a mess which takes longer to sand it clean). I personally haven't used it, so I can't comment to the foldability/durability, but it will withstand REALLY high temps, which aluminum foil won't.