mailbox really empty?

After moving out mailboxes in databaseOld to another mailbox database (databaseNEW) how can I tell if everything is really out of the Old one?
When I defrag it, it was 680gigs now it's 160gig. (If it's truly defragged / compacted it should be way less that 160gb)

What could be taking up the space?
Room resources are on New, Public Folders are on new...so what the heck is left?? How can I tell?

Thank you..

Brett