McDave has it...if you can't get the nocks out with heat, you should be able to find the appropriate sized brass rod from a machine shop or hardware store. I have two about 8" long (one for axis, one for regular shafts)...slide it in the shaft from the other end (without insert) and slam it up and down with gravity...it usually knocks out the most stubborn broken/glued nock. Sometimes works for stripped inserts too.
I try to remove inserts as LKH does if they are not stripped and someone else put them in. When I put them in with JB weld, they ain't coming out, at least in my experience.