Krud Kutter 32 Oz Rustex is a rust inhibiting coating which converts rusted metal overnight into a rust retarding, paintable surface. When applied, rust (iron oxide) is chemically changed to a hard substance that becomes a paintable surface. Increases paint adhesion and durability of the coating. For use on rusted metal surfaces to eliminate rust and promote adhesion of a fresh coat of paint, Covers up to 150 Sq Ft per 32 Oz bottle. Before applying product, remove loose paint and heavy rust with a wire brush and clean surface well. Apply product directly to rusted area, wait overnight, apply primer undercoat and paint, Heavily rusted surfaces may need two coats applied. Water based, bio-degradable formula.