"Hydrotropic solutions are aqueous salt solutions which effect increased solubility of substances insoluble or slightly soluble in water at the same temperature. It is a salting-in effect as compared with the more commonly known salting-out effect. Relatively concentrated salt solutions are required to effect a marked change in solubility of the third component. In general, the third component is reprecipitated by diluting with two to three volumes of water. The solvent may then be made ready for re-use by reconcentration by evaporation."