A pair of adjustable plyers to do the twisting should do the job. Start twisting up by the button and work towards the back. At one point the rubber will pop loose. It's all metal under the rubber.
This photo might help.
That's a good idea too!! I had used up my patience by the time I decided to look at other options and using my knife on it seemed like a good idea.....plus I have to admit that I took a small amount of pleasure in cutting it.......cutting it deep I say!!!