if you can get the other cup out and BB leaving just the threaded ring in there ive managed to extract one before by expanding an old quill stem with the wedge inside the tube, clamping a pole into where the handlebar would normally clamp and then turning it out.
if you can get the other cup out and BB leaving just the threaded ring in there ive managed to extract one before by expanding an old quill stem with the wedge inside the tube, clamping a pole into where the handlebar would normally clamp and then turning it out.
edit/pic might explain