To better clean the visible part of the extruder, it is advisable to first bring it to a temperature of 200 °, doing so all the burrs of material, they will soften. At this point you can proceed with a sheet of absorbent paper or a cloth to clean the outside of the heating chamber from the presence of smudges.

NB. the paper or cloth, they will be in contact of 200 °, then use tweezers or the like to exert pressure, never put your finger near the temperature extruder.