Remix for this great spool holder: https://www.thingiverse.com/thing:508896
I noted that small pieces of foam did travel to nozzle, due filament was pushed thru sponge.
Now filament travels between two sponges, after cutting pieces it is easy to clean sponges = no leftover particles.
Lid is just rotated / leveled from original.
Made to use with 4mm (OD) ptfe tube.
edit 130218: added model for 6mm (OD) tube, not tested!
You may play with resolution and infill.