a machine for treating or processing , e . g . injection moulding or extruding , plastic material which is available in packaged form said machine comprising , in a manner known per se , an extrusion nozzle and a feed channel connected thereto , is combined with a device for emptying the packages into said feed channel by deformation of the package . before the emptying exit openings may be provided in the packaging material by means of special perforating members . the deformation and the emptying of the package takes place in a cylinder by means of a piston fitting therein and driven by means of pressurized fluid .