Other than cleaning with an air duster… any other recommendations to keep the gears clean?
Hello @Sylissimo 
and Welcome to the Creality Forum…
What kind of filament and brand are you running through it…?
Just curious as maybe some brands are more “dirty”…? Hmmm…?
Isn’t the filament supposed to go through the wheels and not the gears?
Based on the color, either Inland ABS or Creality Hyper PLA rainbow color. The Creality was the filament that was clogged in the extruder.
Just to compare I have the same extruder and don’t see much filament crumbs on the gears. Mine doesn’t get all that much use but maybe yours does…
Small brass wire brush, about the size of a toothbrush should scrub that off, something like these perhaps I have a load of wooden handle ones but I can’t remember where I got those from. I take it the gears are fairly easy to remove?