During the 3D printing process, some of the extruded filament may stick to the nozzle surface. After the nozzle cools, these filament residues will solidify on its surface. If not cleaned in time, they may cause nozzle jams or leave dark marks on your next print.
At least once every two weeks.
Be careful of the hot nozzle surface!
Do NOT scrape against the black thermal insulating casing during cleaning.