Not knowing exactly what your snap rings are- I'd guess they are flat spring steel, about 2 coils worth. If this is the type and If you look closely, you can find an "end" to the spring. Pry it out with a small bladed screw driver and work the spring( you'll probably need two instruments to do this) around the circumference of the cylinder till it pops out. To replace, insert one edge of the coil into the groove and work the spring around the groove.