From premixes containing different amounts of water and relatively constant amounts of the detergent and solvent dry cleaning solutions with the desired final concentration of detergent are prepared. The water solubilizing power of the detergent is determined by visula assesment of the optical density of the solutions, and, after adding water to those solutions that are still clear, the solubilized water content for a given concentration of detergent is determined. The water emulsifying power of the detergent is determined by observation of phase separation in the solutions, and, after adding water to those solutions in which the phases are considered not to have separated, the emulsified water content for a given concentration of the detergent is determined.