Potassium oxalate is used in bleaching agents, as a reducing agent in photography and for rust removal. It is also used in the pharmaceutical industry to purify substances.
In the metal industry, potassium oxalate is used to remove rust and as a precipitating agent in rare-earth metal processing. It's used to bleach textiles and woods and remove scale from automobile radiators. It's also used as an acid-rinse in laundry and in waste-water treatment processes. In the dental industry, potassium oxalate may be used to combat dentin hypersensitivity, a condition in which pain occurs when the dentin is exposed to tactile, thermal, chemical, osmotic or evaporative stimuli.