If their is a sufficient room for the thread, why don't you move them? It really can't be much harder, if at all than deleting them. Whenever Tony has moderated my threads,he has sent me a PM telling me why. You say it takes time? The time spent writing your replies in this very thread, explaining would have done it. If you don't tell them, a thread will arise, again like this one, thus are left doing what you could have done to begin with.
Benni.