Disclosed is a process of recycling and reusing an aqueous degreasing solution for further use as a component of a coolant solution which is itself recycled and reused in metal cutting machines. Also disclosed is a method of degreasing parts, and a degreasing apparatus which is controlled such that an appropriate amount of the aqueous degreasing solution is introduced into the coolant solution. Finally, disclosed herein is a method and system for preparing a coolant in which an aqueous degreasing solution is further utilized as a feeder solution for a coolant solution, with the resulting solution being able to be separated into its component parts and reused in the cutting and cleaning of metals to form metal parts.