Abstract: A mop yarn is produced by extruding onto the embossed face of a conveyor belt a first layer of a fiber reinforced sponge forming viscose mass, feeding regularly transversely spaced core yarns onto the conveyor advanced first layer and extruding a second layer of the sponge forming viscose mass onto the core yarn carrying first layer. The composite layers are then coagulated, regenerated and purified, and the resulting cellulose sponge web is then longitudinally slit to produce sponge strands in each of which is embedded and bonded at least one of the core yarns. The resulting cellulose sponge mop yarn is of rectangular transverse cross section and has low porosity water permeable top and bottom faces at least one of which is embossed and skinless side faces and each yarn has one or more core yarns of cotton twine embedded therein and bonded to the sponge material.