After a team sits completely idle (no posts, huddles, etc.) for several months, the system will remove the team automatically. If you are the administrator and want it removed sooner for any reason, you can let us know what team it is (we need the URL that is shown below the discussion forums on the main team page), and we can check it out and close it if it meets the criteria. Note, if any members are still posting in the team or have done so recently, we would want to leave it open. You can reply with the team URL here if you want and I can take care of that.
Also, note that if the team does stay open for a while, it is okay for the admins to quit their team leader role and leave the team as well if they do not want the leader role to continue.
Just let me know if I can help.