Abstract: A mixture of propyleneglycolmethylether and propyleneglycolether which is added in a ratio of 60:40 and 90:10 to the last rinsing bath in which metal parts are cleaned, in order to achieve intermediate corrosion resistance.

Abstract: A cleaning agent composition and method, especially for cleaning electronic components, optical parts, and circuit boards. The liquid agent is completely CFC-free and biologically harmless. The composition includes a dipropylene glycol monoether and one or more of the following: N-alkyl-lactam; dihydro-2(3H)-furanone; a polypropylene glycol ether; R.sub.4 --CH(--OH)--CH.sub.2 --NH.sub.2 ; N(R.sub.5).sub.3 ; R.sub.6 --N[(CH.sub.2 CH.sub.2 O).sub.n H] wherein R.sub.4 is a chain of 1-6 carbons, R.sub.5 is a chain of 2-18 carbons, R.sub.6 is a chain of 8-18 carbons and n is a number between 2 and 25.

Abstract: A process isolates, in a closed circulation, the soluble fluid carried over into a rinsing bath from said rinsing bath and to return the fluid into the upstream bath. To this end, enrichment by separating the soluble fluid from the rinsing bath is provided, the enriched fluid, which has been carried over, is returned into the upstream bath together with solvent, where the solvent is separated out with the use of a membrane.