I got a bunch of old .223 from a friend of mine who got it when he left the army about 15 years ago. The cardboard boxes look like they might have been water damaged, but the ammo on the inside is still seated fine, with some discoloration in the casings. Nothing more then on the Federal surplus I buy. Think its safe to shoot? Or anything I should do to prep it to shoot? I know quite a few of you shoot older surplus ammo so I figured you might have some suggestions.