This super-simple filament cleaner is inspired by a very old model found on Thingiverse. Extremely lightweight, no moving parts, no magnets, simple to print, no supports needed.
The casing is angled upwards 30° so it won't put additional strain on the filament path. The back has a circular slot designed to fit around the feed tube retaining clip; just make sure the green clip is pointing downwards so it's not in the way.
You'll need a small piece of foam, 15mm thick and about 60mm long, with both ends cut at a 30° angle (use scissors); simply fold it in two and slide it into the cleaner.
Updated 2023-12-11: version 2 now includes a small tab on the inside curve that fits in the small notch left by the green clip; this prevents the cleaner from moving around when the filament retracts. Unfortunately, this means adding a small cutout to the back which will need a bit of support during printing.
The author marked this model as their own original creation.