Got a Megachip recently from a seller on Amibay, also picked up one of those cheap-o PLCC extractor tools. Was super-excited to put it in but that darn tool wouldn't work worth a %#% - just kept slipping out and scratching the top of the chip, or making awful crunching sounds when I'd try to squeeze it in around the edges. 
Finally gave up on that, pulled the motherboard, flipped it over, stuck a driver in those two little holes and tapped it with a hammer till Agnus popped out. Little did I know that those two holes didn't actually line up perfectly with the holes in the socket so I wound up chipping the base of the socket, but it seems like minor damage and the Megachip went in fine and works great with no issues. PLCC - what a terrible design, however!
Yes, those PLCC extractors off ebay are s@@@! I scratched my 68882 on my 1200 trying to use the dam thing. Its easier to use the access holes below like you did. On my 500 some b@@@@@@ glued Agnus onto the base of the socket so the socket came off the board leaving the pins lol.
