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In the 65 year old boxes of ammunition that came with my rifle are a few cartridges with some greenish or whitish spots on them. Pictured are the worst two. I’ve heard that these shells are still useable and can be cleaned up by wiping the stuff off with a cloth, or possibly scrubbing with one of those teflon safe kitchen scrubbers. I have also heard to be sure to not use any chemicals. Any recommendations as to what I should do with these?

Fine steel wool or a brass brush will work. With age they do corrode and the brass can become brittle.You may have some split necks when you shoot them.