Extruder cleaning filament is a purging compound for plastic extrusion systems offered in a convenient form for 3D printer operators.
Temperature range from 130°C to 260°C. Actual usable temperature may vary due to differences in extruder construction.¹⁾

1. Set extruder temperature to match filament in use.
2. Pre-purge the extruder with natural colored filament (matching the filament type currently in use) to initially flush the extruder of color and contaminants.
3. Unload filament.
4. Slowly feed cleaning filament into hot-end. Use a series of stop-and-go motion to feed the material. Allow the purging compound to dwell for some time in the hot end before extruding it out the nozzle. The extrusion from the nozzle may be discolored and feel rough from carrying contaminants.
5. When the extrusion is clear and smooth, cool down the extruder.
6. When starting with new filament, set extruder temperature appropriate to the new filament. Feed new filament to purge the cleaning compound from the hot end.²⁾

• eSUN (invented) Cleaning Filament 1.75mm 0.1kg
  http://www.intservo.com/products/new-clearning
  esun_cleaning_filament_-_general_instructions.pdf

• eSUN 3D Printer CLEANING Filament 1.75mm Natural 0.1kg 1.75mm Cleaning
  https://www.amazon.com/dp/B00MVIYNFW
  esun_cleaning_filament_-_general_instructions.pdf

• Inland 1.75mm 3D Printer Cleaning Filament
  http://www.microcenter.com/product/442003/175mm_3D_Printer_Cleaning_Filament

• MatterHackers - Cleaning Filament - 1.75mm (0.10kg)
  https://www.matterhackers.com/store/3d-printer-filament/cleaning-filament-1.75mm

• Monoprice Premium 3D Printer Filament 1.75MM 0.1kg/spool, Cleaning Filament
  http://www.monoprice.com/product?p_id=12504

• ToyBuilder Labs - Prototype Supply Extruder Cleaning Filament 100g
  https://www.toybuilderlabs.com/products/extruder-cleaning-filament

• Ultimaker - How to apply the Atomic Method?
  https://ultimaker.com/en/resources/19510-how-to-apply-atomic-method

• 3dverkstan.se - The Atomic Method
  http://support.3dverkstan.se/article/10-the

• bukobot.com - Nozzle Clearing
  http://bukobot.com/nozzle-cleaning

• hydraraptor.blogspot.com - PLA pipe cleaner
  http://hydraraptor.blogspot.com/2014/07/pla-pipe-cleaner.html

• instructables.com - 100% Solved - Clean blocked extruder nozzle in 3D printing
  http://www.instructables.com/id/100-Solved-Clean-blocked-nozzle-in-3D-printing/

• teambudmen.com - Steps to clear a clogged 3D-printer nozzle
  http://blog.teambudmen.com/2013/09/steps-to-clear-clogged-3d-printer-nozzle.html

• Ultimaker - How to unclog an Ultimaker nozzle?
  https://ultimaker.com/en/resources/21619-how-to-unclog-an-ultimaker-nozzle

• 100% Solved - Clean blocked extruder nozzle in 3D printing
  https://www.youtube.com/watch?v=JZTeEvJrfzA

• 3D Printer Nozzle Clogs, Effects & How To Fix Them
  https://www.youtube.com/watch?v=SfACwC9diQY