I saw a good method a few days ago on another site. Will post the link if I run across it. It has pics.
I just had the opportunity to try this on a p3800. Remove the fan from the processor case. Lay a case screw on a smooth wooden surface, screw head down. Line up one of the pins on the back of the case to the case screw and press down firmly on the fan side of the processor case. Be careful, the screw will probably want to lean over on your first try. When the screw is aligned properly it only takes moderate pressure (maybe twenty pounds)for the pin to pop out. The pins will (hopefully) be undamaged and the retail fan & h/s can be reused if needed.
BTW, don't do this on mom's or wifey's kitchen table. The screw head will leave marks! My processor came through undamaged, your's may not. Try this at your own risk.
HTH
Phil