Starbrite Rust Stain Remover is the best way to eliminate unsightly rust stains from boats, RVs, exterior walls of homes or wherever else they may form. The formula begins working on contact, dissolving the oxidation that causes these stains. Easy to use; spray directly onto stained area and rinse off; no heavy scrubbing needed. Removes rust stains from fiberglass, metal and painted surfaces Easy to use; spray on, wipe off and rinse clean. Features: Easy to use spray on formula, No rubbing or scrubbing required, Safe for use on fiberglass, metal and painted surfaces, Removes rust drip stains and sprinkler rust deposits, Contains no harsh acid, Great for cleaning corrosion stains caused by metal hardware, nuts, bolts and other marine fittings, Specially formulated for marine and RV use; Also ideal for removing sprinkler stains. Directions: Spray Star brite Rust Stain Remover directly on surface to be treated. Let product work until stain is gone before rinsing area with fresh water. Deep stains may require a second application and light scrubbing with a brush or cloth. To help prevent future rust stains, apply a protective coating of Star brite Polish to cleaned area to seal surface pores. Avoid contact with fabric. Test area to be cleaned for colorfastness in an inconspicuous area before proceeding with overall cleaning.