As far as I can tell, (I've looked at how to do this on one of my spare clusters) You've got to pry the clear plastic face off, which is difficult because it's just glued on. However, it is poorly glued on in some cases, and it is possible, but you should go slowly, and try to cut around the glued seam with a razor blade (knife). taking the back of it appart wont help at all.