If you don't have a thread cap if you have a thread stand use it to thread the thread up through the loop at the top so the thread comes off with the spool horizontal and up to the hook or loop, then thread it normally bypassing it hitting the ends of the thread at all. I have to do that with some of my embroidery thread that is cross wound; if it's the small spools, when the thread spool gets low it sticks in the ends and breaks; this helps stop this. Good luck. I too have filed down the ends of the spools, knife, file, scraper, whatever works to get the nubs off the ends.