A solution of nitric acid and alcohol, Nital, is used for etching of metals to reveal the microstructure.

Commercially available aqueous blends of 5-30% nitric acid and 15-40% phosphoric acid are commonly used for cleaning food and dairy equipment primarily to remove precipitated calcium and magnesium compounds (either deposited from the process stream or resulting from the use of hard water during production and cleaning).

Nitric acid is also used in explosives, and is one of the key components of Nitroglycerin and RDX.

Digestion
In elemental analysis by ICP-MS, ICP-AES, GFAA, and Flame AA, dilute nitric acid (0.5 to 5.0 %) is used as a matrix compound for determining metal traces in solutions. Ultrapure acid is required for such determination, because small amounts of metal ions could affect the result of the analysis.

Woodworking
In a low concentration (approximately 10%), nitric acid is often used to artificially age pine and maple. The color produced is a grey-gold very much like very old wax or oil finished wood (wood finishing).

Other uses
Alone, it is useful in metallurgy and refining as it reacts with most metals, and in organic syntheses. When mixed with hydrochloric acid, nitric acid forms Aqua Regia, one of the few reagents capable of dissolving gold and platinum.

Aqua Regia is technically a reagent –– not an acid. You make Aqua Regia by (carefully) mixing three parts of hydrochloric acid with one part nitric acid. That mixture produces nitrosyl chloride and free chlorine gas (in the aqueous solution). These two agents are individually exceptionally powerful oxidizing agents. Combined, each acid performs a different function. This is what gives Aqua Regia the ability to dissolve gold and platinum –– where neither acid by itself was able to dissolve the metals by themselves.