well I would boil it that will make sure that the die of is gone even from places that you can not get at to scrub. the rock is dead anyways. To glue apoxy works well get aquarium save stuff. I don't use anything the worms inthe tank seem to like to bond stuff together on there own. After a couple of months it will still move but not that easaly, alittle nuge will not topel it at this point.

Bill

Bill