Abstract: Disclosed is a process for separating components of liquids in industrial processes for cleaning of articles. The process is directed toward a terpene-based cleaning system including washing and rinsing of contaminated articles and which further includes separating components of used wash and/or rinse solutions into component parts so that terpene components of the solutions can be recycled for further washing and the water component of the solutions can be purified and recycled for rinsing. The method can include filtering a stream directly from the wash solution to avoid fouling of the filter. The method also includes using a cross flow filter having a pore size of between about 50 .ANG. and about 7,500 .ANG. to effectively separate water from remaining components of the contaminated wash solution.