a method of using a plastic extruder equipped with an extrusion die and a gloss controlling auxiliary die to produce an extrudate of polymeric material having controlled gloss appearance comprising the steps of first extruding an extrudate of polymeric material through the extrusion die and then passing the extrudate immediately after exiting from the extrusion die through a gloss controlling auxiliary die which is kept at a temperature either higher or lower than the temperature of the extrusion die .