Take a flat blade screw driver and pry or tap the beveled end of the ring outward till one edge begins to come out. Then simply pry easily around till it comes out.
I use a sharp centre punch to make an indent as close as I can get it to the hub and close to one end of the clip, then a scriber to prise the end out of the groove.
Before refitting it, I grind the end of the clip so that there is somewhere for a screwdriver to get a grip next time.