Auto-kill old threads?

There have been quite a few "un-earthings" of old threads lately.

How about automatically closing a thread that is inactive for more than a month or so?

Also:
How about auto-killing all threads in which a newcomer posts a question (often homework) and is never heard from again. I'd even consider auto-deleting said member....

When a thread is a certain age you can't use the quick reply feature, and the main reply does (to my knowledge) have a banner with a message about the age of the thread. If members still ignore this then so be it really.

some threads which are not even replied can be removed also the threads which are meaning less i guess so.

but all the old thread not, because some are solved so the information on each reply may be usefull to some other

Old threads still have merit, in some cases or all cases. If the person who replies to revive a thread has similar problem and the solution in the thread doesn't resolve it, by all means I say allow members to bring up old threads. Some threads go unsolved as well and get buried, if someone wants to contribute, let them. If you don't want to contribute, just skip it and go to the next thread, it's that easy.

And homework questions are okay, just let them know they'll learn more if they do it themself. Maybe give a hint and point in right direction, just don't shrug them off or give complete answer. It's that easy.