Haven't tried them, Tomoko. I think the infections from rubber bands are more about the size of the covering than the material.
But Andy, it's easy. Slice them quickly and cleanly with something very sharp and do it outside the tank like im_buford mentions. Let the mamma and frags mucus up for a bit, tie the frags to a piece of rubble somehow, then provide good clean water and lots of flow. That's all there is to it.