I got this wedge a few weeks ago (originally made by Avery, now sold by Cleaveland):
http://www.cleavelandtool.com/Close-Qua ... zJrRyFr0eEI was on the fence about spending almost $20 for a simple wedge like this, but this thing has rocked my world. I know a lot of builders make small wedges and/or grind down rivet pullers to accomplish this task. I did this as well, but found myself spending tons of time dealing with jams and weakened tools. This just saves such a phenomenal amount of time and lets me use the pneumatic puller for almost everything. For the time saved, it is already definitely worth the money.