An aqueous metal working liquid

The present invention relates to an aqueous metalworking liquid, which has the form of a clear solution at 20 ° C., is precipitated at a temperature higher than 20 ° C. and contains: (a) a polypropylene glycol compound containing 6-100 propyleneoxy groups and lacking the presence of hydrocarbons groups having more than 12 carbon atoms, and (b) at least one water-soluble anionic compound, selected from the group consisting of a phosphate ester or an ether carboxylate, the anionic compound containing 1-40 oxyalkylene groups having 2-4 carbon atoms and lacking presence of hydrocarbon groups with more than 12 carbon atoms. The metalworking liquid has excellent lubricating properties and can easily be worked up and reused without leaving troublesome coatings on the metal surfaces.