Archive old sites?

Is there a way to archive old sites?

We are a 3PL so we acquire new sites and decommission sites as well. As of now we are having to add "zzz" to the beginning of old sites so the choice moves to the bottom of the list. If I delete the site, then the old ticket data moves to site not set. I would like to keep my ticket history and be able to take this choice away form users to lessen the amount of choices.