They handle being fragged very well however the skeleton is quite dense and strong so the easiest way is to use a saw of some sort. I've used a diamond wheel on a rotary tool, wet tile saw and wet diamond bandsaw. But if you want to be really low tech just grab a chisel and a mallet. Usually I try to cut around the polyps but sometimes I go through and they heal up anyways. You could probably do anything and they'd still heal just fine.
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