Jeu de forets de précision pour le nettoyage ou l'agrandissement des buses
This handy set of drills, can be used to refine, clean, or enlarge a nozzle to a larger orifice. Lets say, you have a 0.4 mm nozzle thats seen better days, but it's still a nozzle. Drill it larger, go to 0.6. There you go. New life for a used nozzle.
TIP: It's a good idea to leave a small flat around the nozzle opening. You can run a nozzle across a soapstone to add a flat ring around opening.