Removing kenya trees?

So I have read you can just pull them off the rock, or cut them with a razor blade, and scrub the rock so it does not regrow. My question is, from my understanding is it will release toxins, so does that mean I have to take them out of the tank? Or is there a safe way I can do it inside my tank? I do not want my fish or other corals to be harmed. I only have a 29 gallon bio cube. Any suggestions, i can remove the rock if necessary but I would rather not have to, because the kenya trees i want to remove are on a big base rock.