I have been digging to the back of the ammo closet and found some .303 I bought several years ago. It is marked 42 or 43 and most of it looks fine. There are a few pieces with some rough, black and green corrosion. I was planning on pulling these bullets and dumping the powder, but how does one tell if ammo is safe to shoot? How much or how deep of corrosion is too much to be safe? Is any corrosion too much?