Hi, I am aware is not recommended to clean the old coins, but most if the coins in my collection have been poorly stored and handled so far, and I'd like to rinse them to remove the fingerprint/sweat traces. What would you recommend to do in this case. I'm not interesting in scrubbing any dirt or to change the surface in any way. But I understood in time the fingerprints and sweat can damage the surface. Any advice? I also imagine there might be different substances to use depending on the material each coin is made of. I would appreciate any opinion or guidance in this matter. Many thanks!
I personally do not clean coins but that's just me I know a lot of members do and swear by it, but from my understanding if you do want to clean your coins then you want to use 100% acetone. Dave
Also, I was told and follow, if you do "rinse" them afterwards you'll want to use Distilled Water (and not reuse from coin to coin) and then use a, for instance, blow dryer to dry the coin.
Howdy Andreea - Here's the thing about fingerprints - when they are fresh they can be safely removed. But if they are more than a week or two old, odds are they are not coming off short of using a commercial coin dip. Fingerprints, when they get on metal, become semi-permanent because of the acids in our body oils. They literally etch their way into the metal. And it doesn't take very long for this to happen. In regard to the basic question you asked about rinsing coins, without harming them, there are 4 things that are safe to use. 1 - distilled water 2 - acetone * 3 - xylene 4 - coin dip *** But even with distilled water, acetone and xylene care has to be taken and you have to do things the right way. I explain the right way in this thread - https://www.cointalk.com/threads/proper-acetone-procedure.193708/ The same procedure that I describe there for using acetone should be used for all three. It is also important to note that none of these 3 will remove toning, they will have no effect on toning. The asterisk for acetone is there for 2 reasons. 1 - it has to be pure acetone, not fingernail polish remover. And 2 because of copper. That's because if acetone is used on copper coins, sometimes those coins turn a weird color afterwards. So it is best not to use acetone on copper unless you absolutely have to. With copper, try distilled water first, then if that doesn't work use xylene. The 3 asterisks are there for coin dip because it should only be used by those who have a lot of experience with using it. Coin dip, if not used properly can ruin a coin, it will literally strip the luster right off a coin, forever making it a problem coin. But when it is used properly it will do things that nothing else can.
For rinsing, I would restrict myself to pure solvents, as @GDJMSP mentions, water, acetone and xylene with coin dip reserved for experiments and to when you learn how to use it. However there are other solvents (non-reactive) which can be helpful, including isopropyl (rubbing) alcohol, ethyl (grain) alcohol and certain hydrocarbons including hexane and toluene. Many of these carry risks and you should always be careful. I have become a believer in patting the coins dry (no rubbing) since I did an experiment letting solvents dry on coins and had bad results. The drying with a hair dryer might be OK too, but I still prefer a pat-down.
I should have mentioned in my previous post that if fingerprints are fresh, acetone and or xylene will remove them simply by soaking the coins in it for a while. Sometimes they can be a bit stubborn so I've always just recommended soaking them overnight.
To illustrate what is being discussed here, this Franklin Half had a serious case of finger print, so I soaked it in distilled water, followed by Acetone and lastly xylene, each for a day. As you can see, the finger print remains, although the appearance is somewhat enhanced.
