Posted By:
Al C.risafulliIt's all about the Dremel tool. I just slice vertically across the slab, underneath the flip, about halfway through the plastic. Then I insert a flat-head screwdriver into the notch I created, and pry upward. Usually this breaks the seal, and the top half of the slab pops right off. Takes a couple of seconds, but usually avoids any shattering.
Yes, I break slabs for my raw collections, too. 
-Al