Rust-Oleum Stops Rust Rust Reformer converts rust into a non-rusting paintable surface. Rust Reformer eliminates the need to sand bare metal and creates a smooth, flat black coating with excellent rust and corrosion resistance. Spray directly onto rust or rusty metal surfaces for indoor or outdoor use. Oil-based formula provides Stops Rust protection and dries fast. Apply one coat and allow 24 hours before top coat.