Disclosed are metal cleaning formulations and methods of use. A formulation of the present teachings comprises one or more furoate esters such as ethyl 5-methyl-2-furoate and methyl 5-methyl-2-furoate. The formulations further comprise a base oil, which can be, for example, a naphthenic oil, a synthetic oil or a combination thereof. In some embodiments, a formulation can further comprise a metal protection additive and a lubrication additive. A variety of base oils, metal protection additives, and lubrication additives are suitable for use in the present teachings. Formulations of the present teachings are especially useful for the cleaning of metal products such as firearms. The cleaning power of a formulation of the instant teachings can exceed that required for US Military Specifications.

Provided is an acid-pickling additive for a surface oxide scale of a stainless steel material, a preparation method thereof and an acid-pickling method. The acid-pickling additive consists of 1 to 10 parts by weight of an alcohol amine compound, 0.1 to 5 parts by weight of a metal complex ligand, 0 to 10 parts by weight of a nitrogen-containing organic cyclic compound, 0 to 3 parts by weight of an alcohol compound, 0 to 3 parts by weight of a plant extract, and 1 to 2 parts by weight of water. This acid-pickling additive can solve the problems of high energy consumption, environmental pollution, and high cost in the existing method for removing an oxide scale of a stainless steel.

A composition for application to a metal substrate comprises a metal cation, an azole compound and an aqueous carrier. A composition for coating a substrate comprises a carrier comprising an epoxy carrier, a urethane carrier, or a fluorinated urethane carrier, and an azole compound. A coated substrate includes the composition for application to a metal substrate and a coating on the composition. A method of fabricating a coated substrate comprises applying the composition to a substrate, allowing the composition to dry to form a conversion coating, and applying a coating on the conversion coating.