I first clipped the hanging ring off of the top end. Then I cut the icicles in half into uneven lengths using a hack saw. I cut them at an angle so they would lean out in random directions when based. I then glued the cut halves onto rough circles I had cut from foamcore. Finally I textured the bases with Woodland Scenics snow.
I'm very pleased how they came out, and I think I will also try making a few and spray painting them and then painting them up like rocky spires for more conventional Sci-Fi and Fantasy games.