fun finding wheaties like this isn't it? Keep looking , you never know what you'll find. I look at local Flea mkts too. Sometimes they don't know or care what they have, and got some pretty good deals.
That 59 D looks nasty. At the least I would give it an overnight soak in distilled water and a good brushing with a toothbrush before drying it in an oven on low for an hour or so.
if you are thinking about staying with the hobby you can get a " coin red book" 2022 is out already someone mentioned in here. Most bookstores have it or check Ebay. Good luck and have fun.
