Chemically, acids are the preferred way to remove rust stains. Rust stains which come from iron in the water supply, 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 (it is highly toxic and must be handled with care).

Lemon juice (citric acid), or white vinegar (acetic acid) are mild acids which may resolve the rust Stains problem. In the corner of an affected area, you can test both acids. Apply the acid with the clean sponge side of a white, nylon scrub pad backed sponge (available at supermarkets). Agitate with the scrub pad side. Rust stains are the result of oxidation. Rinse thoroughly afterwards and blot dry.

It is noted taht, never use the 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, sponge, etc. Rub discolored surface until stain is removed. Rinse. Wipe dry and polish.

To remove heavy, stubborn rust stains you can use oxalic acid stain remover compounds such as Zud or a tri- chloro-melanine compound.

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.