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.

Abstract: A visual comparator for use in evaluating the nature and extent of contamination in a solvent used for cleaning mechanical parts. The comparator comprises an opaque frame, and an array of viewing apertures is formed in the frame. Each of said apertures is covered by a translucent viewing panel, with certain of the viewing panels comprising a first array having a graduated sequence of predetermined colors and optical densities, each indicative of a given level of soluble liquid contamination. The remainder of the viewing panels comprises a second array having a graduated sequence of graduated optical densities, each indicative of a given level of contamination by suspended particles.

Abstract: A test apparatus for use in determining the concentration of oils or other soluble contaminants in a petroleum hydrocarbon solvent. The apparatus includes a positioner for a two-layer fibrous sheet, or two separate sheets, in either case providing an upper layer of material that is sorptive to polar materials and a lower layer that is absorptive to non-polar hydrocarbon liquids. When the contaminated liquid evaporates either, as by being heated, a characteristic stain indicative of contaminant level remains on the lower layer. The method includes applying contaminated solvent, separating particulates in the upper fibrous level, and allowing the soluble materials to stain the lower layer. Some embodiments of the apparatus include built-in heating and air circulation means.