One problem associated with tightening groups is nock damage.

As you can see in the below picture, sometimes they get pretty much destroyed. This leaves very little to get a grip on when trying to remove them.

All hope is not lost, however. As you can see from the closeup on the left, there is a small hole in the middle of the nock. Take a fine screw and screw it into this hole a little way (far enough to be secure). I used a guitar pickup screw as these tend to be very slim.

This gives you a more secure point of contact to pull on compared to the remainder of the nock itself, effectively using the screw like a corkscrew. Grab your pliers and give it a tug, the nock should come free fairly easily.

All that remains is to inset the replacement nock, and turn to the…