A dark patch on the outside of a nozzle and a blocked filament passage are different problems. Before reaching for a brush, identify where the plastic is collecting and which coating is on the nozzle.
Where is the residue?
| Location | Next check |
|---|---|
| Small deposit around the tip | Read the nozzle maker’s exterior-cleaning instructions. |
| Plastic returning around a threaded joint | Investigate the assembly using the hotend service guide; repeated wiping does not repair a leak. |
| Inside the filament passage | Use the feed-resistance checks before deciding on an internal cleaning procedure. |
| A large mass surrounding wires | Stop and use the printer’s documented blob-removal or service procedure. |
The coating changes the tool choice
E3D’s Volcano cleaning guide permits a brass brush for several listed metal nozzles, but rejects steel-wire brushes. Its Nozzle X section lists a different cleaning allowance. Do not extend the brass-brush permission to every coated nozzle.
Should I clean it hot or cold?
Use the exact service procedure: it must specify temperature, power state and access around the heater and sensor wires. A generic suggestion to brush a hot nozzle leaves out those important details. Keep tools away from electrical connections.
What if the stain remains?
Color alone does not tell you whether a nozzle is worn or obstructed. Check whether deposits continue to transfer to prints and whether extrusion behaves normally. Do not escalate to an unapproved abrasive just to restore a shiny appearance.
Before the next print: confirm the permitted cleaning method, inspect for recurring leakage, and restore any removed cover exactly as the service guide requires. Persistent buildup deserves diagnosis rather than a more aggressive brush.
