Do you have a drill press? There are many roads to Rome so to speak, but when dealing with bone and ivory which are extremely prone to cracks and breaks, I've had the most success using my drill press to drill out the pins.
If not, you'll probably want to file those off, very carefully and slowly. Flush cutters will also work, but be careful not to force anything.
You'll need a 1/16" punch to push out the pins, again, don't force anything.