Here we go again

Another question about coin cleaning. I tried the search box and got nowhere. Anyway I know about the no-no's of cleaning coins. I have mostly silver coins and have never cleaned one, but I recently bought 50 rolls of copper cents at an auction and there are many with bright luster on part of the coin, with dark areas on the raised spots, probably from fingerprints. Is there any product or way to regain the luster on the dirty spots without losing the original nice luster spots?? Thanks!

 

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As has been stated thousands or maybe by now, millions of times, leave them alone. You will gain nothing by making them pretty with luster if the coin has been damaged. Read many other post here on cleaning coins. However, if you don't care about the coins value, if not a collector, if you don't care about the coins at all, just dip them in battery acid, TarnX or any powerful copper pan cleaner. They will shine like new but be worth about .01 each

 

However, in the interest of human advancement, it might be worth the time to find a few common cents with similar problems and perform some experimental cleaning. Just as an uncirculated coin that has been circulated but shows no sign of wear is still uncirculated, a cleaned coin that shows no sign of cleaning is still an uncleaned coin. [Hint: acid probably isn't the solution and I don't know what is or I'd be doing it myself].

If you manage to do this successfully so that it can't be detected even under magnification, remember to call it "conservation" and not cleaning.

This is the Holy Grail of numismatics and you might become famous, rich, or both if you can do it. Expect it to be difficult and require an unconventional approach unlikely to have been attempted by others.

 

I agree with cludsweeper99 to just experiment with a few of the coins you don't realy think are worth much. However, be careful of possible error coins such as double dies, RPM's, offsets, etc. Don't use them for experiments. Just for your information I played around with cleaning some time ago and tryed using: Kerosine, Acetone, charcoal lighter fluid, battery acid, citric acid, coke, lemon juice, gasoline, fuel oil, dishsoap, laudry soap, auto hand cleaner and just about anything else I could find laying around. One interesting observation was the dish soap turned the copper coins bluish.

 

The most adventurous I've been....well on coins that I'd keep if I removed the junk on them, is grey electrical tape. It doesn't leave a black gooey residue like black electrical tape, and is flexible enough to be pressed in between the details on a coin. Removes 50 years of dirt off a wheatie, but won't do much for corrosion or finger prints.

The most tortuous I've been to a coin was to sandwich a nickel between two zinc lincolns, wrap them in aluminum foil in such a way as a long portion of it forms a handle...then set it on the kitchen burner, flipping often to keep the foil from melting.....

the zinc melts before the copper with some odd results...and the nickel is left perminantly blackish....mainly b/c it was literaly sintered. Was really hoping it would turn a more interesting color than black....but I'm no chemist.

But yah, bottom line is as others have stated...there is no known surefire means of cleaning without damage.

 

That's quite an array of experiments you've tried which worked the best and which was the worst?? Since I'm not really interested in pennies I tried some tarnex on an unciculated common date, well thats not the answer, it took the darkness out of the coin but it looks very washed out, I think I dipped it to long. Also tried it on 2 pennies that had black dusty looking crude on them so bad that the date was not readable, those I dipped for a long time and some of the crud came off but the reverse turned coppery and silver color. As luck would have it and the date now readable they were dated 36s and 33d. Oh well the dates were unreadable before the dip anyway. I heard WD40 works I'll try it on one coin and someone mentioned the elec.tape, I'll try that to. I got about 50 rolls of wheats in a box with other coins at an estate auction otherwise I never would have got them, I dont like pennies.

 

The bad thing is that even when someone does come up with a surefire way to clean a coin with no evidence, even at 60x magnification, nobody will try it.

 

Sometimes I feel like the only lesson that will drive home the point that cleaning coins is a bad idea, is to just tell someone to go ahead and clean them. Let them find out the price for being too tidy. It could be an inexpensive or an expensive lesson but the mistake would only be made once.

 

Well like I said on my original post that I am not one to clean coins and have never cleaned any of my silver coins. But there is a point at which a coin is so unattractive and ugly that a cleaning certainly will do nothing but improve it. And if all these cents were not in a box of other stuff that I wanted I would not even have them, I just want to get rid of them, I dont collect cents except for the draped bust ones.

 

As I already said I've tried just about everything I could find to clean coins. I've only done it on coins that were already messed up or of little coin value. With copper coins that have a green type corrosion on them it is usually from a reaction of the copper with a sulfur type acid in the air. I've found it is easily removed with any good base. I've used baking soda in distilled water to dissolve the contamination, however, it must be noted that the greenish material is partially copper meaning a loss of material on the coin. This is common in areas where sulfur rich coal is burned such as in mills, factories and power stations. Traces of SO and SO2 enter the air, combine with H OH, a Hydrogen Hydroxide none as water, to form air born sulfurous or Sulfuric Acid. This attacks copper coins, piping, etc and forms CuSO3 or 4.
For cleaning with out damage the only thing I've been able to find is Kerosine or Acetone. Then a distilled water rince and hair dryer blow dry.
The worst thing I've used is putting a coin in Coke and leaving it there for a week. Heating coins over a stove just turned them different colors similar to dish soap. I've tried WD40 and several other similar products that made the coiins shine but after a good rinse with water and hot hair dryer, ended up looking pretty much the same as when I started. Tarn-X really makes all coins shine but I've leaned that if one on top of the other you must remember to stir occationally. Phosphoric Acid and pure Amonia are similar to Tar-x and I wonder if it contains some.
Hoever, if you value a coin don't do any of the above.

 

So does that mean sandblasting is out??? Just kidding. We hear ya Moen, just some of us get the bug to experiment from time to time

 

moisture coins

what about coins contaminated with moisture and sticky stub. do we have to separate them with other coins?. can this affect other coins if keep together even with silicon pack now in place?.

 

Tracy5900. Try to remember that tarnishing, corrosion, toning, etc on a coin is not like a contagious thing with living creatures. It shouldn't bounce from coin to coin. I say shouldn't because what ever caused a coin to get some type of damage from it's invironment may also effect the other coins in the same area. Also, try to remember that it is not the moisture that effects coins but the contaminates in the moisture. Pure moisture, which is nothing but H OH, other wise called H2O, will not effect metals except a few like Na, Sodium. The higher forms of metals do not react with the H OH radical or that type of covalent compound. However, keeping moisture as well as just air should keep the coins looking like new for a few hundred years. Try it and let us all know in a few hundred years if it worked.

 

<Science=OFF>If one lincoln has verdigris on it (green fuzzy stuff) and you stick it next to another lincoln without it.....call it magic, but in time you will have two lincolns with verdigris.

<Science=ON> For a detailed explaination of verdigris check out >THIS< site

Bottom line, yah, if you keep your coins in a true vaccum, devoid of everything save the coin, then it will never corrode. Reality is, if some coins have junk on them, that junk will affect the other coins.

 

Please, please stop calling the green contamination on copper coins Verdigris. I'm not sure who started using that term but obviously was not a chem major. Verdigris is caused by the copper coin coming in contact with Acedic Acid forming Cu(C2H302)2.H OH. Please forgive the lack of lower case numerics. The 2 and 3 and 3 inside the () should be lowered but don't know how on a computer. That is known as Copper Carbonate. That is very unlikely to be the cause on coins. Unless you or someone has a source of Acedic Acid, that is not what causes the green colored contaminate. Copper reacting with normal air born contaminations of SO and SO2 with H OH forms a Sulfurous or Sulfuric Acid that creates CuSO3 or 4. Also, a greenish formation.

 

Please note I'm not saying all green corrosion on coins is NOT Vertigris, I'm just stating that the chances are very, very slim. Being a chem major turned Electrical Engineer, I once did a thesis based on air pollutions effects on everyday substances. Again, the chances of a coin coming into contact with Acedic Acids substancially suficiently consentrated to create a chemical reactions during NORMAL everyday situations is slender. However, this could be done by human interventions. The largest greenish contaminations on copper coins it usually due to the Sulfur air born contaminations. In some areas this is so prevelent that copper piping is not used due to the disentigration of hte copper. Highly Sulfur Oxide contaminations in the soil has made many organizations change to Stainless Steel grounding systems due to the same metalic reactions. Again, I'm not saying some of the coin damage is not Vertigris, I'm just saying it's abnormal.

 

Don't we mean ACETIC ACID? Or do I need to scamble back to my numinclature texts.

Ruben