You already know the source of the population, overfeeding.
Just cut back a little bit here and there and the numbers of bristleworms will decline slowly. There isnt anything really wrong with having them in a tank, just have to watch out for your fingers when you are working in there. lol If you must remove some I had alot of luck with a bristleworm trap I got for like $6 online. In only two nights I got over two dozen worms. Good luck