Thompson Center Natural Lube 1000 Plus Bore Butter is a biodegradable all natural lubricant which contains no petroleum-based oil or additives. It reacts differently (chemically) to the combustion of blackpowder producing far less tar like fouling. It can also be used to field lube bullets. Bore butter is an excellent rust preventative on external surfaces of any firearm. Features - Seasons the Bore - Will Not Chemically React with Black Powder or Pyrodex - Used as a Patch and Bullet Lube