The surface that Rust Kutter is being applied to needs to be free from oils, grease, dirt and dust. Remove any loose paint or rust with a wire brush or sandpaper. Wipe off any loose residue. Do not grind surface to bare metal. Rust must be present for Rust Kutter to work. Shake Rust Kutter bottle thoroughly and apply with the spray quart container or for the gallon apply with a brush or roller. Immediately after application thoroughly wash brush or roller with warm, soapy water. Allow to dry 24 to 48 hours or until "tacky" feeling is gone.