Yes, sounds like these knives are well used? hehe.. Okay, well I'm guessing they've got pins holding the handles right? These pins are probably rivits and would be tapered on both ends. You can either replace the rivits by drilling them out and installing new ones, or you can "re-buck" them by supporting the back of the pin while tapping the other end with a hammer gently. I would recommend you have this done professionally or take it to a knife shop if you are not a handyman. If you're talking about the hinges, you may need to get new hinges that are larger in diameter, or get bushings or sleeves installed to get rid of the play.