Simple filament dust remover and oiler.
Cut out a kitchen sponge, fitting in the top part (diameter 10 to 15 mm, heigth 5 to 10 mm).
Make a slit in half to center direction and put in between both parts.
Put it around the filament and turn, until it fastens.
Optional put some oil into the open holes.
This assembly will keep your filament clean during the printing process. Can be assembled without unfeeding the filament.