When Is A Classic Coin Uncollectible?

Put 'em back into circulation and let some young, up-and-coming numismatist have a thrill. This will keep the hobby going more than anything else you can do. I re-circulate wheaties all the time.

If you suspect the coin is not a valuble one and it is all corroded, it makes for a really great item for experimenting. For example you could try all the different liquids in your home to see which one does the best in removal of that stuff on the coins. You take the worst looking ones, soak in Lemon, Lime, Tomato, etc type juices and rinse with either distilled or tap water. The main thing to do is record each step of the experiment. When those fail to do anything, then there is always those Acetone, Laquer thinners, Alcohols, lighter fluids and on and on and on. Eventually you will become rather an expert on what to and what not to do in the cleaning process so when you see someone on this forum saying things like "I used lighter fluid and it worked perfectly." You could jump in and say something nice, mild, uninsulting like "Your an Idiot, you know"