Does anyone have a tip to remove the screw on back? I have tried a tool with a rubber "cup" and handle, but I respect the input of anyone else.
Thanks,

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I use a two or three inch diameter loop of Scotch packaging tape with the sticky side out and my first two or three fingers inside the loop.

This method works well for me for both removing and installing screw on case backs and bezels, and for loosening tight backs and bezels.

I especially like the control it gives me so that the risk of cross threading is minimized when screwing on a case back or bezel.

On bezels you want to be careful that you don't loosen the crystal in the bezel by twisting to hard. I usually try and make sure the tape is rolled over and stuck to bezel as well as the crystal.