The tool for removing the cylinder needs to have a bevel on it. I used a piece of metal coat hanger and filed a nice long bevel. A bike spoke might be too hard to file, but a grinder would probably work.

When you insert the tool, the straight side (without bevel) should be flat against the cylinder and the beveled side away from it, that way the point can get behind the retainer clip and open it up. If you don't have the correct bevel, you won't be able to insert the tool past the clip.