It is sorted ascendingly or descendingly by the last post. You can customize it if you want.
https://bitcointalk.org/index.php?board=39.0;sort=last_post;deschttps://bitcointalk.org/index.php?board=39.0;sort=last_postYou can sort it with replies, views and others but in general, it is still messy. I guess that there is a fixed transition time before those locked and moved threads with leftover messages will be automatically moved to trash can. If OP want to propose something, it can be reduce that transition time and those threads will disappear after one or two hours or immediately after moderators moved those threads to other boards.