Abstract: A method of manufacturing a usable container that includes supplying, by a first screw conveyor, a first thermoplastic plastic material for the outer container to an extruder, supplying, by at least one second screw conveyor, at least one second thermoplastic plastic material for the inner bag to the extruder, cutting at least two, preferably diametrically opposed, holes in the outer container at a lower edge region of a shoulder section, inserting pins vertically through the holes, between the inner bag and the outer container to loosen the inner bag from the inner wall of the outer container, exerting an increased pressure from an exterior through the holes onto the inner bag, or producing a reduced pressure in the inner bag to detach the inner bag from an inner wall of the outer container.