So...I'm curious... Clearly, one is advised to never clean old coins. Is there, however, a difference in 'types" of cleaning? Are some acceptable if done correctly? For example... Certainly one wouldn't want to "clean" a coin with anything abrasive, or polish it to make it "nice and shiny". And, of course, dipping has its own supporters and detractors, and pros and cons of course. But what about coins with 'gunk" on them. Dirt, grease, etc. Is it considered acceptable to "clean" these coins in the strict sense of the word...that is, remove dirt. If so...how? Should one soak them in only water, or maybe soapy water? Is it acceptable to use slightly "harsher" things such as vinegar? Or is it, on the other hand, simply never allowed to alter a coin...even if what's being altered isn't actually the coin, but dirt...in any way?
That is why they have companies like NCS , that have and know how to properly use solutions that will best remove the contaminants on a coins surface. There are all sorts of concoctions folks have tried to clean coins. If it's worth saving, NCS is the right way to go. I'm certain others may disagree.
Properly cleaning coins is and always has been accepted. The key is not doing any damage to the coin, or altering its surfaces in any way. So any method that will remove dirt and or grime and not do that is perfectly acceptable. But therein lies the problem. Using a cloth of any kind will damage the coin, same for any brush no matter how soft it is. And soap of any kind, any cleaning liquid or detergent, pretty much anything you would use for cleaning around the house, is strongly not recommended. That's because all of these household cleaning agents leave traces behind on the coin, and in time those traces of chemicals will damage the coin. Even plain tap water is harmful to coins, not only because of the chemicals it contains, but also because of the various minerals found in tap water. So that doesn't really leave you with much to use. The one thing you can use is distilled water, and some will say to not even use that, but to use deionized water instead. Of course you can also use acetone on non copper coins, but even acetone can cause copper to turn all sorts of weird colors sometimes. Same thing for stuff like vinegar, Coca-Cola, tomato juice, any citrus juice, olive oil, ketchup, taco sauce - and on and on and on. All of these things will clean coins, but the reason they clean coins is because they contain an acid. The acid is what does the cleaning. But it also alters the surface of the coin, thus turning any coin so treated into an instant problem coin. This is why what you will normally hear is to just not attempt to clean coins. It's becauae just about anything you try to use will cause harm of one sort or another to the coin. Yeah you can try the distilled or deionized water - but they don't do much when it comes to cleaning, hardly anything at all. Now you can dip coins, in a commercial coin dip. And then rinse and neutralize the dip. But any circulated coin you do that too looks like a coin that has been cleaned. And some will even say it has been harshly cleaned because circulated coins just don't look like that. And if there had been any remnants of luster left on a circulated coin - the dip will likely remove it. And again, you end up with a coin that will be said to have been harshly cleaned. Yeah, there are some chemicals out there like whatever it is that NCS uses. But nobody knows what NCS uses, or how they use it, or how long they use it. So you tell me - is there an acceptable method ? If there is, I don't know what it is.
That's a really terrific breakdown, thanks. Great infor for consideration there. After reading all that a couple times, only one thing comes to mind...sonic cleaning in a bath of RO/DI water seems like it would be fairly safe, presuming we could somehow suspend the coin in the water, rather than having it vibrating/sliding all around the bottom of the tank. Beyond something elaborate like that, you make a valid point I think.
Sonic cleaning doesn't cut it either. Many a coin have been ruined (turned into body-bag material) by using that method.
Huh...really? Could you explain how/why that could happen? I would think, with no physical contact, there'd be no chance for wear, and without chemicals, nothing to attack the metals. Not saying I doubt you (clearly, I'm the ignorant one here *heh*), just trying to understand the mechanisms by which coins can be damaged.
I can't explain the chemistry or physics of it and don't pretend to be able to. All I can tell you is that many coins come out pitted and/or with altered surfaces.
To my best understanding, sonic cleaning could potentially remove any spots in a copper (and possibly other metals) that have impurities in the metal. This would give it a pitted surface. So, technically if you had a perfect coin with noimpurities on either side of the coin you could safely clean it in that manner. But, of course you wouldn't know until you actually sonically cleaned it. You can carefully remove surface dirt and grease with acetone. But, attempting to remove corrosion, dullness, or oxidation will result in surface damage for sure. Best advice: if in doubt, do not attempt cleaning.
Nor, for that matter, would one need to clean it to begin with. *heh* That's what I'm getting here...it's not so much that it's impossible, but rather that it's almost a certainty to damage the coin without an expert's tools, touch, and knowledge...so why bother?
I think you stated what I have failed to, gboulton. I will add one thing though. If you are going to improperly clean a coin, sell it on ebay. There will always be someone it will be good enough for. Trust me!!!
That may be true, but do you truly feel that it is the ethical thing to do ? Have someone else pay for your mistakes ? I believe those who consider themselves fellow collectors or numismatists have more integrity than that. Why promote bad behavior with suggestions like that ?
*heh* Well, for the record, I don't have any coins in need of cleaning...by me or any experts...at the moment. *heh* I really started the thread because I encounter some pretty grungy examples while roll searching, and wondered about the process should I ever encounter one worth the effort/expense. Having said that... If I read quartertapper's post correctly, I think he was suggesting that even a damaged coin will find a buyer on e-bay even when correctly described. I don't believe the point was so much "There's someone you can fool with any lie" as it was "There's someone who'll buy any junk." To be sure...I'd agree, if the intent is to mislead, I'd find that unethical. if, however, the intent is to unload correctly described coins via an open, honest, uncoerced transaction then...hey...whatever trips the buyer's trigger works for me.
