+1 on Hillrider's suggestion! I apologize for confusing it with Sheldon's idea, back in December. I think Hillrider's idea is actually even better, because although Sheldon's concept works very well, I have destroyed a fixed cup with it. That was a double-wall cup, with a recessed area for a seal--the pressure from Sheldon's removal tool crushed the double wall. Hillrider's idea would have allowed me to use an external wrench on the flats and get enough torque to remove the cup safely. He's right, there are commercially-made tools which do the same thing, but his invention works just as well.