Paul: If you haven't dried them out yet, you need to scrape all the meat/fat off the backstrap sinew then stretch it out on something to dry. The leg sinew usually comes out clean enough to just hang up and dry. I like to use the legs for bow backings, and backs for wrapping and tying. four legs aught to be enough to back a bow.
I've tried hammering and combing out the legs and just recently learned how to hammer and strip em. Just hammer between two rounded rocks, rip the whole thing in half, then the halves in half - so forth and so on till you get them small enough to start stripping the size of individual fibers you want. Time consuming but way more efficient than combing in my experience (less waste).