Nah, don't bother - I don't
We reached a decision some time ago that if an existing thread is too old to be resurrected with new posts, then there is no harm in making a new thread on the same subject.
Deleting them doesn't do us any favours because the search engines will have logged them already and then if a visitor clicks on a link but it's a dead end, they probably won't bother trying our site out any further...
For the record, Sword of Aeons