You mean paper fibers?
Yeah I had that problem also.
What I did was to put the front of the paper against the non-stick sheet and the fiber side against the blotter paper. That kept the fibers off the front of the print.
I think there were less fibers as I used the book, the fibers being transferred to the back of the prints. Been a while, so I don't remember the details.
I also did not PRESS the blotter book with the prints inside, since in class we dry mounted the prints. That may have also been a reason I got less paper fibers on the front of the print.