Nitric acid is a highly corrosive acid, and powerful oxidising agent, used variously in the manufacture of fertilizer, munitions, and demolition grade explosives. However, largely thanks to its oxidising nature, it also makes for a useful cleaning agent, as well as in etching process for the manufacture of electronics. There are several grades of purity, ranging from fairly low (68%) concentrations, up to red- or white-fuming nitric acid at concentrations over 95%. According to the industry standard classifications of purity, nitric acid ACS reagent grade exceeds specifications set out by the American Chemical Society for use in analysis and industrial processes that need to meet high quality requirements. Examples of the uses of high quality nitric acid include in the detection of traces of metals in solutions, as an aid to the digestion processes of sludge, water or solid samples and in electrochemistry. However, the main industrial use remains the production of fertilizers, although low concentrations are also used to artificially age wood, producing antique-look furniture.