grind the heads off carefully with a dremel grinding wheel. . pop reflector out, and replace with new one. The re-pop ones may need a tad of grinding to fit in the old housing, and may need a dab of silicone , or J. B. Weld to hold in place. Replace the metal backing plate over the ground down heads and put a dab of J.B. Weld on each one, and let set overnight. J.B. Weld is the best thing since canned beer, and will fix many things from cracked frames to broken brackets on a chain guard. It is a very strong two part epoxy , that is sold in hardware stores, Automotive parts stores and Home Depot, for about 6 bucks.