I generally use a round burr in my drill - I have a foot-switch so I can control speed from about 200 rpm to 20,000 and use a flexible drive. Using it right at the low end of the rpm scale, simply grind off the top of the rivet, releasing the collar. The pin will then just push out the other side. WARNING! needs a steady hand and a bit of patience, but its the easiest way i have found. Hope this helps