Abstract: Various cleaning compositions useful in cleaning oil and carbon residue encrusted metallic surfaces are described. The specific formulations of the present invention may include a variety of non-corrosive and non-hazardous materials which include an aliphatic ether of a propylene glycol and/or an ester thereof, an alkanolamine, an aliphatic fatty acid blend, an alkyl pyrrolidone, water and, in some applications, a mild caustic such as ammonium hydroxide, for example. The various formulations of the present invention combine their ability to dissolve or emulsify a combination of deposits commonly found on auto and aircraft engines and the like. These formulations are most effective in removing or dissolving soils, such as oils, greases, varnishes and like residue from oil, fuel, solvents and other sources.