What is the best way to completely remove the residue of a broken graphite shaft in a driver head? There is nothing to grab onto as the shredded material is flush with the top of the hosel.
It just takes time. Drill, then a reamer if you have one. Some heat. I use an awl to get down into the corners, and then a wire hosel brush drill attachment to finish it off. Make sure the hosel plug, at the bottom of the bore is still there.