mine came off really easy, i can pop them off with my fingers. the key is if you are using a screwdriver, make sure you are pressing against both tips of the C at the same time, that will cause it to spread open slightly and pop off, if you just push on one side, it will just spin around the shaft.
also, it is easier if you push in on the plastic actuator that the clip rests on, that will take the pressure of off the clip, making it easier to get off, just be aware that the plastic actuator is spring loaded, once the clip comes off, it could go flying...so be prepared.