If by "ruin" you mean "utterly destroy", the answer is yes. If by "ruin" you only mean "damage", the answer is still yes. Have you searched the forum for threads on cleaning coins? Do you realize that in the numismatic context "cleaning" and "severely damaging" are synonyms? Or, are this thread and the one on baking soda some kind of satirical exercise?
It is used on dipped out copper to recolor the coins. It works, but will only fool an inexperienced collector. My suggestion is to not clean the copper in the first place...Mike
It can help darken awful looking toned coins, but they will still look unnatural. Few would be fooled by it. There are better ways to darken cleaned copper than putting chemicals on the coin.
Don't leisten to them. Go and distroy all the coins you want with that stuff. They are yours. However, if you ever want to get rid of them, you may as well just take them to a bank. As for a darkener, why bother buying anything when there are so many free things to use. For instance bury the coin is wet dirt for a few years, spit on it every day for a few years, put it in a charcoal type bar-b-que grill while someone is cooking and so many other ways to ruin a coin. Why not just throw them against a brick wall? As to cleaning a coin, just swallow it. The acids in your stomach will clean the coin. The only problem is the recovery of the coin is messy.
If you keep posting these cleaning questions, I do believe Just Carl will get out the horseradish and eat those coins himself. If you clean your coins, you'll never be able to show them to someone who really understands coins without feeling squirmy about the cleaning. They'll know. Even worse, you're likely to develop an eye for coins yourself, and it could bother you every time you look at them. Sorry to sound like Great Aunt Doris, but you can't undo a cleaning.
Cleaning is forever. I sent in a coin dated 1875 to be slabbed and guess what? It came back cleaned! I talked to the experts and was told that it was a very old cleaning probably done over 100 years ago and had since re-toned with age. So does cleaning or any treatment damage a coin? Well 130 years later and the cleaning was still evident. I would say it's pretty much permanent.
Even worse, you're likely to develop an eye for coins yourself, and it could bother you every time you look at them. Sorry to sound like Great Aunt Doris, but you can't undo a cleaning.[/QUOTE] Not entirely true. An arc welders torch has been able to completely undo any signs of cleaning. Another method to eleminate any signs of cleaning would be to dig a hole in your yard, fill with gun powder, add gasoline, your coins and light. This method should make it difficult to find any trace of cleaning if you can find the coin.
