...With all due respect, this advice is strictly from a coin collector's point of view, & there's no arguing this point: ...guys, be aware that your tumbling methods are going to greatly reduce any numismatic value the coins may have ... shining coins to try & enhance their appearance is a huge no - no ... you can take a $100 coin & reduce it's value to $10 or less, by using this method ...
... there is one method amateurs can use to try & remove material from a coin: soak in 100% acetone (cheap & available at stores like Target, Walmart, etc. ... ). Acetone will not affect the metal, & will remove organic gunk such as loose dirt, glue, tape, oil, etc. Soaking can take anywhere from hours to weeks, to a month or more, depending on the coin's surface condition. Be patient. After soaking in acetone, do not rinse in water. 100% acetone will quickly & completely evaporate by itself. Water can contain corrosive minerals such as lime, fluoride, chlorine, etc., that will eventually undo what you're trying to achieve ...
...if you use water to rinse in the field, you should follow up at home with an hour's 100% acetone soak, to remove any minerals attached to the coin's surface ...
...While in the field, resist the urge finger-rub dirt & sand off of a coin ... that's as bad as tumbling, &, again, can greatly reduce any value a coin may have. If you don't have a little water with you, or, nearby, be patient & wait until you're home & can properly rinse & soak the coin as described above ...
...I'm gonna refer to the recent New England tree coin catch/spill mentioned on this site ... by cleaning & damaging the coins' surfaces, these guys may have reduced the coins' values by 60% or more ... heartbreaking ...
...I apologize if I've offended you, is not my intent here, but, you may appreciate this info in the spirit in which it is given ...
...In closing, I would suggest your taking any coins of questionable value to a dealer in your area, & get some advise before over-cleaning the coins ...
