I just found tiny white flakes affecting the gears on my 3D printer. I can't do a chemical analysis to confirm but I am 99.9999999% certain that's PLA debris from the brittle sample filament that built up over time.
By the way I don't know if you've scrolled through some of my past blog posts but I made a few about 3D printing before I got my 3D printer. Probably the most "epic" one was a post about a YouTube video in which a woman was walking around with a functioning delta printer on her back.