I found these same bits in the original 800k floppy drive of my 512ke after I took it out of my closet and felt confident enough to restore it. The floppy drive had been basically shot (with short bouts of functionality) ever since I got it, and had only deteriorated from there. When I replaced it, I found pieces just like those rattling around. I never did determine with certainty exactly what they were, but circumstantial evidence led me to suspect that they were part of the read/write head assembly.