Effectively removes heavy rust, scale and bluing without damaging your expensive firearms or parts, because it attacks the rust, not the base metal. Works great on both steel and cast iron without dangerous fumes; does not cause hydrogen embrittlement. pH neutral solution won't eat your clothing or bench. Does not attack softer metals like brass, copper, zinc or aluminum so there's no need to remove inlays, sight beads or solder-on ribs before immersion. Highly concentrated liquid really saves money. One gallon of Brownells Steel White can be diluted with water to make up to 20 gallons of safe, economical, rust and blue removing solution. Removes light rust and bluing in as little as 5 minutes; immerse in solution longer for heavier rust or scale. Works great at room temperature but can be heated to 120° F. to increase speed of rust removal. Per instructions use 5 to 1 ratio for heavy rust.