Rust stains come from iron in the water supply, which can only be permanently remove through installation of an iron filter. Occasionally iron is dissolved from rusting water pipes or mains by corrosive water. Iron stains can be removed by a weak acid solution, usually oxalic acid which is highly toxic and must be handled with care. Never use chlorine bleach as this sets the iron stain.

Fresh iron stains on plumbing fixtures such as sinks, bathtubs and chrome will generally yield to treatment with heavy duty cleaning compounds containing large proportions of trisodium phosphate. Apply cleaner with damp cloth, pad or sponge. Rub discolored surface until stain is removed. Rinse. Wipe dry and polish.

Heavy, stubborn rust stains can often be removed by oxalic acid stain remover compounds such as Zud or a tri-chloro-melanine compound such as Barkeepers Friend. Follow directions carefully.

For rust stains already set on bathroom or kitchen plumbing fixtures, dissolve oxalic acid crystals in hot water and add enough whiting or talc to make a soft paste. Apply this poultice to stain and let dry before removing. Rinse and polish. Use with care-it is poisonous.

This article was written by Anne Field, Extension Specialist, Emeritus, with references from Purdue Extension bulletin Iron Control for the Home.