Etching zinc or copper plates for intaglio printing using dilute nitric acid.

The removal of scale from hard water from sinks, taps, toilet bowls, washbasins, baths, kettles and steam irons. All use some form of acid as the active ingredient.

The corrosion resistance of iron and steel can be improved by treatment with sulfuric and phosphoric acids. Other metals are also affected through the introduction of chemicals.

The provision of an electric current at fixed voltage from a number of lead-acid cells in series. The use and maintenance of this equipment.