A new member of the site recently bumped a For Sale thread that had been inactive since 21/10/2007 - and it's likely after this amount of the time that the item is not available or perhaps the member isn't interested anymore.
Similarly, threads in the lounge entitled "Nonsense" are probably worth keep for no more than a few weeks unless it's active. Maybe cold deals could be removed after period of inactivity too, as they are not deemed hot enough that people would want to use them?
Maybe it would help the forum (server and members) for these items and maybe more to be purged after a period of inactivity to ensure the forum doesn't continue to be cluttered after. Or is there already a purge procedure in place maybe?