I recommend this because it has worked for me on Oyster casebacks, gen and rep. you need super glue, isopropyl alcohol, a socket and a ratchet. glue the socket head to the caseback with the super glue, attach the ratchet and simply remove the caseback. Once the caseback is off, soak it in isopropyl for several minutes (15-30) to remove the socket head and then wipe the remaining super glue off (it will have turned to a gel from the alcohol soak.
This absolutely works and it works everytime and the glue will absolutely come off with enough soaking in alcohol. Good luck