I know your done cleaning by now, but I just wanted to clear something up. You can use a dish soap to clean with, just rinse repeatedly, same as the bleach. Neither will be absorbed into the rock and any will be removed in the boiling process. Baking is up to you, as it could cause cracking. (put it in a cold oven and raise the temp).
You can stick it together with silicone tank sealer so it doesn't fall and hurt the fish or tank.
Dr Joe
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