Oxalic Acid refers to an acid that works as a reducing agent for metal oxides to remove tarnish as well as for rust and ink stains. It is used commercially as a wood bleaching agent, laundry rinse, and calcium remover. It can remove some paints and varnishes. It is also used as a mordant in dyeing textiles and the manufacture of ink. It is a reliable and effective cleaner when used in appropriate applications. Oxalic Acid is used to remove rust and other difficult stains from areas such as boats, buildings, swimming pools, wood decks and many more.