Thanks! I will open the packs, check them and transfer to either ammo cans or plastic containers w/ silica gels paks, and get rid of the cardboard.
Did yours get wet or was it just moist, ambient air while in storage? Do you know what actually caused the corrosion? Just curious...
What I was told, regarding the German ammo, was that some of the cardboard was not quite up to spec (slightly acidic), and caused corrosion where the brass contacted the cardboard. It was restricted to the immediate contact areas only; you’d have corroded rounds all around the perimeter and clean-as-a-whistle in the middle.
Green corrosion can usually be wire-wheeled off; if it’s turned pink, look at salvaging it for components. The pink supposedly means that the zinc leached out of the brass and only copper was left, which could cause case failure on firing. Real shame; people sought that German surplus almost as intently as Australian for its accuracy.
The Portugese battlepack ammo, on the other hand, apparently did get wet along the way. OTOH, if you can find Portugese ammo on machine gun links, that stuff’s clean and reliable, though it seems to hit a bit low.