These guys are correctomundo...probably have tried it just like me. It unravels the carbon fibers 9 times out of 10. One thing I have always thought might work, but have never tried it is to get some super glue remover or denatured alcohol, remove the nock, position the arrow so the insert in down and the nock end is up, and pour it down into the arrow from the nock end. Maybe let it set for an hour or so and then see if that has loosened it up at all. The downside could be though that the chemical might weaken the carbon down around the insert after working on it like that. Might be worth a try...