Is it ok to store my ammo in them? I picked up 4 .50 cal cans with the markings on the side at a show this past weekend. They looked fine on the outside with the exception of a few marks, but the insides were pretty bad. I managed to clean them up pretty good except for some rust in the cracks and crevices on the inside. I coated them with a light layer of oil and let them sit for a few days before loading them up with 1000 rounds each of 5.56 in factory packages. So is it ok for the ammo to sit in these sealed cans despite the slight rust that I couldnt get out? Long term how does the condition of the cans affect the ammo?

Youre good. Leave them in the factory packages though just so loose rust doesnt end up getting inside your gun. The main thing you want to keep from getting in your ammo can is moisture. So if theres no holes then dont sweat it