Process for the cleaning of articles or surfaces and a cleaner bath to be used in the process

Process for the cleaning of articles or surfaces using a liquid cleaner of low viscosity containing N-methyl-2-pyrrolidone by immersion into a bath, which process comprises keeping the water content of the cleaner at desired low values of at most 20% by weight, preferably at most 10% by weight, calculated on the total weight of N-methyl-2-pyrrolidone and water, by means of a water absorption preventing layer applied on the surface of the cleaner and comprising at least one liquid aliphatic hydrocarbon, which is immiscible with N-methyl-2-pyrrolidone and has a straight, branched or ring-closed carbon chain, or microballoons or microspheres of a hydrophobic material which is insoluble in N-methyl-2-pyrrolidone.