I wish to unsubscribe to old topics, cause they keep coming back in my unread replies page. But i can't find an option for it. Is it even possible?
If you are using the watchlist, then you can just click the "unwatch" link.
If you are using the "Show new replies to your posts", then you should switch to using the watchlist, and you won't have such a problem anymore. Then you can just click the "unwatch" link.