Particles in clear PETG

I noticed black particles in a clear filament with now clue where they came from. They are flexible almost like rubber. Using Bambu P1S, using slow print settings. I checked the belts, print head and various rubber components and can’t find anything. Anyone have ideas?

I noticed black particles in a clear filament with now clue where they came from. They are flexible almost like rubber. Using Bambu P1S, using slow print settings. I checked the belts, print head and various rubber components and can’t find anything. Anyone have ideas?