Abstract: The present invention discloses a synthetic post-pickle fluid composition which is useful for treating metal to provide corrosion resistance and act as a lubricant for further metal processing. In the preferred embodiment, the composition contains an aqueous solution of a base and a carboxylic acid. The composition may also include fatty acids, viscosity controllers, i.e., thickeners, extreme pressure additives, and optionally may include a chelating agent. In a second embodiment, the composition contains an aqueous solution of a base and a fatty acid at more then 7 percent of the total composition. Examples of suitable bases include potassium hydroxide, monoethanol amine and diethanolamine. Examples of suitable carboxylic acids are the aromatic carboxylic acids and C.sub.4-16 dibasic carboxylic acids. The composition has a basic pH.