RE: Properly disposing of OLD ammunition
Have you considered talking to a gunsmith? A 'smith would be far more qualified and interested in inspecting your old firearms and determining if they, and the ammo you have, is safe to fire.
Wolfkiller,
Why do you think his local police dept. would have any interest in disposing of his ammo? Police officers have enough on their plates already to worry about handling and disposing of his decades old ammo. I'm also not quite sure why you think that a police officer is any more qualified than anyone else when it comes to firearms in general. Sure, they have and shoot their duty weapons, but I know several cops that have no interest or knowledge in guns beyond the operation ad maintenence of their duty weapons. I'd bet that an officer wouldn't want anything to do with his ammo. He's a cop, not a garbage man. The only way he's probably going to get a cop interested in taking his ammo is if he shoots someone with it.
shanach,
First, I'd say that you don't have anything to worry about handling that ammo. I've handled and fired ammo that was surplus WWII ammo and never had a problem. Ammo doesn't become unstable with age, and the worst thing that can happen is that the ammo over time had become inert somehow. I'd strongly recommend that you take the guns into a gunsmith and have them safety inspected. He'd also be able to give you a rough appraisal of their value, especially if he knows you're not interested in selling them (to him at least). The rifle you have is probably an 8mm Mauser 98, or possibly an Italian 6.5mm Carcano. A gunsmith/dealer would be able to tell you for sure.
Good luck,
Mike