Cleaning Copper-Nickel coins

[Figleaf]

I understand, lonshrim. Stains are normally the result of a substance reacting with metal, e.g. a fruit picker with fruit juice (acids) on his hands handling the coin. There's no way you get them out, except by removing the affected metal, which will destroy your coin. Save to buy a better copy or live with the stains.

Peter

[Kid Romeo]

While ketchup is acidic and vinegar (and lemon juice) is extremely acidic, olive oil should not be acidic a all. You use acids on badly corroded silver. It reacts with metal, so you will quickly come to the point where you are destroying, rather than cleaning the coin. To remove dirt, you can use soap, which solves grease. However, soaps work only for a limited time and if it is perfumed soap (practically all soaps are perfumed), it may react with metal or remove patina.

Peter Olive oil is acidic. Olive oil is composed mainly of the mixed triglyceride esters of oleic acid and palmitic acid and of other fatty acids. Cleaning of coins is an act in itself of destroying a coin's numismatic value (or so I know). Acid reacts with metals and that's why cleaned coins or altered surface coins by chemical means are rejected by TPG and are considered problem coins. Soaps are acidic too. Try doing litmus paper test.

....and if you spill some on your skin, you should wash it off immediately and not expose your skin to sunshine.

Acetone is not much harmful for skin; it only dehydrates it. I handle acetone with naked hand and wash hands.

By using a wooden (wood is softer than metal) toothpick, you can speed up the softening and cleaning process: soak, pick and soak until yo are happy.

LOL

As a bonus, olive oil will give copper and bronze coins an attractive, deep colour.

You sure you not teaching MS how to doctor a coin.

[Figleaf]

Now that all sounds too doctrinaire (American) to me. Cleaning does not necessarily destroy value. Bad cleaning does, but consider the coins shown here. All of them are cleaned. They came out of the ground dull grey. I'll post a picture of what they looked like before cleaning in that thread. Consider a common modern coin wrapped in a layer of crud. Do you collect coins or crud? The problem is not whether to clean but what happens if you clean too aggressively.

TPG is completely irrelevant outside North America. Suppose you have cleaned your coins aggressively (I did when I just started collecting at age 6). I can assure you that only a few decades later you cannot distinguish between a harsly cleaned coin and one that wasn't. Of course, bad cleaning increases wear, but the only problem in problem coins is time. Hairlines, you say? You won't see them on a VF coin unless you use a microscope and even when you find them, it doesn't tell you anything about cleaning. Clothing made of synthetic fibre also makes hairlines. The real problem is restricted to deep, parallel hairlines on unc and proof coins, because you can see them with the naked eye if you hold them in the light at a right angle. That's why I discourage cotton wool. It's typically used on high grade coins.

Pure olive oil and soap are base. Most soaps and a few olive oils contain additives that react with metal. First press olive oil will contain no harmful substances, because the stones of the fruit are little or not pressed. Lower quality olive oil will contain harmful substances from the stone, but not in a meaningful quantity. Cooking olive oil may contain all kinds of additives, even lemon juice.

Peter

[Kid Romeo]

Now that all sounds too doctrinaire (American) to me.

Yeah, I know.

Cleaning does not necessarily destroy value. Bad cleaning does, but consider the coins shown here. All of them are cleaned. They came out of the ground dull grey. I'll post a picture of what they looked like before cleaning in that thread. Consider a common modern coin wrapped in a layer of crud. Do you collect coins or crud? The problem is not whether to clean but what happens if you clean too aggressively.

Well cleaning does take away some value off the coin no matter how mildly done. If somebody offers to sell you a cleaned coin and an uncleaned of the same grade and same price, which one will you buy? The example you have given is of something of historical importance and rare. That's conservation and not cleaning. Cleaning coins with crud is also conservation IMO but cleaning coins for eye appeal is unacceptable to me. A coin looks best in it natural circulated state rather cleaned circulated state.

TPG is completely irrelevant outside North America.

Can't say so. The world coin section in PCGS and NGC set registries are red hot in competition. Not in the league of US coins but atleast collectors are competing.

Suppose you have cleaned your coins aggressively (I did when I just started collecting at age 6). I can assure you that only a few decades later you cannot distinguish between a harsly cleaned coin and one that wasn't. Of course, bad cleaning increases wear, but the only problem in problem coins is time.

Altered color, hairlines in same direction in coin's surface, dirt accumulation near the legends or hard to reach devices, white residue, zigzag hairlines over a small surface area are all tell tale signs of a cleaned coin that won't go away with time.

Hairlines, you say? You won't see them on a VF coin unless you use a microscope and even when you find them, it doesn't tell you anything about cleaning. Clothing made of synthetic fibre also makes hairlines.

I agree but that doesn't call for voluntarily making hairlines over a VF coin using wooden toothpick.
Any type of clothing will make hairlines if the coin is wiped instead of patted.

Pure olive oil and soap are base.

On the contrary Peter, pure or virgin olive oil is the most acidic whereas refined olive oil is acid free. You are right about the additive part though. BTW The only non acidic soap available in India is advertised as containing 1/4 moisturizer .

[Figleaf]

Can't say so. The world coin section in PCGS and NGC set registries are red hot in competition. Not in the league of US coins but atleast collectors are competing.

Them is American collectors. They are a class by themselves. It's hard to find a US coin in a coffin here and I never even saw an entombed Canadian coin. I bought a framed Baltic state coin in plastic once, but broke it out immediately as otherwise, it wouldn't have gone into my album with all its brothers and sisters. I guess Americans have bigger houses, so they can store tons of plastic. I think the myth "you can't grade coins unless you are a professional", along with the myth "you can't clean coins unless you are a professional" were invented by those who profit from them. Mmm. Maybe I should start the myth "you can't identify coins unless you are a professional" and enrichify myself shamelessly as if I were an investment banker

Here's a little test for you. Take a silver unc coin, say a Georgian rupee, that's been kept in paper for a few decades or so. There'll be an ugly yellow and black patina along the edges and smudge in the deeper incuse lines. Now take a soft eraser and rub. Is this now a) a restored coin b) a doctored coin or c) a cleaned coin? My answer: all three and I'd buy it.

Peter

[Kid Romeo]

Them is American collectors. They are a class by themselves. It's hard to find a US coin in a coffin here and I never even saw an entombed Canadian coin.

Yeah getting them is tough outside America but where there is will there is Ebay. You won't find slabs with Indian dealers but have to source them from the States. I personally know the guy who is now ranked #1 in PCGS British Indian set registry. He is from Bombay. If you have money to burn, slabs are the way to go.

I think the myth "you can't grade coins unless you are a professional", along with the myth "you can't clean coins unless you are a professional" were invented by those who profit from them. Mmm. Maybe I should start the myth "you can't identify coins unless you are a professional" and enrichify myself shamelessly as if I were an investment banker

Can we be partners???.....please; or else I have to steal your idea.

Here's a little test for you. Take a silver unc coin, say a Georgian rupee, that's been kept in paper for a few decades or so. There'll be an ugly yellow and black patina along the edges and smudge in the deeper incuse lines. Now take a soft eraser and rub. Is this now a) a restored coin b) a doctored coin or c) a cleaned coin? My answer: all three and I'd buy it.

First of all, a silver coin stored in paper for decades will get naturally toned. People pay hefty premium for NT coins compared to blast white silver. And you think toning is ugly. Strange
Anyway IMO the Rupee coin would be a doctored coin for me, a restored coin for people who hate toning and cleaned coin for TPGs .I too would buy it provided I get it below catalog value for the grade.

[MS]

Here's a little test for you. Take a silver unc coin, say a Georgian rupee, that's been kept in paper for a few decades or so. There'll be an ugly yellow and black patina along the edges and smudge in the deeper incuse lines. Now take a soft eraser and rub. Is this now a) a restored coin b) a doctored coin or c) a cleaned coin? My answer: all three and I'd buy it.

Peter

I see I left behind a nice little discussion yesterday 

I may not know much about numismatics and I do read up as much as I can. I see how people feel strongly against cleaning coins and I have seen many dire warnings on many threads in many forums about the valuation of the coin plummeting.

Personally I would not think twice about buying such a coin for a variety of reasons.

• I collect coins for myself not to make money of it today. Its future value is meaningless to me. If I have something valuable then I probably will not benefit from it in a monitory sense simply because the damn coins will outlive me. I know people say that to support/expand a coin collection, buying and selling coins is a good way forward and their point is valid too. Nevertheless if I reach such a stage I am happy to leave my undervalued 'doctored' coin out of the business.
• Does the value of the coin really go down? Maybe if you tried to sell to a sly dealer/numismatist might use it as an excuse to bring its valuation down. If the coin itself is not damaged in anyway then I would call it opportunism. I doubt if a dealer would want to sell a coin for a fraction of its value. Plus how many dealers do you know claim that their coins are never cleaned?
• I want to collect coins for reasons more simpler and perhaps inane in the larger scheme of things such as a coins value. I want to be able to hold a coin and marvel at it's intricate detailing and to be able to reflect on its history. Sometimes such reflections can be very sobering. A clean coin gives me more to appreciate than a dirty one no matter how blasphemous that may sound. Just don't nail me on the cross for it.

[Kid Romeo]

All good points MS and I do partially agree with some of them.

I too never care much about coin values unless of course I am making a buying decision and I have to make sure that I'm getting value for my money. I am not against coin cleaning and many times I opt to buy a cleaned coin if I get a good deal. I am against some coin cleaning techniques though and the school of thought that shinier is prettier and circulated is not. Coin cleaning for treating verdigris, fingerprints or crud is OK with me.
Also you might say that you are satisfied with your collection of cleaned coins on which you have spend considerable amount of money and are considered junk by market standard. I wonder whether your heir will have the same thoughts after inheriting your collection, especially if he/she is not the collecting type.

[MS]

I wonder whether your heir will have the same thoughts after inheriting your collection, especially if he/she is not the collecting type.

They are going to dig a 6 feet pit and push me in it and pronounce ashes to ashes dust to dust and I should be worried about they think of my life long coin collection? 

On a more serious note, I have not cleaned a single coin. Still deliberating with more learned people such as those on this forum, reading up the internet etc. I will experiment on low grade common variety coins that's for sure but I will try the gentler methods that we have so elaborately discussed.

Cheers
MS

 

[mumbapuri]

any updates on this topic? would be interesting (read educating) to see before and after effects pics of the experiment (and experience)

[MS]

I have been meaning to buy pure acetone and experiment but haven't got around to actually doing it.

One weekend I was actually asked for it in a couple of shops, the shopkeepers promptly handed me a bottle of acid  LOL

[mumbapuri]

acid would be a bit of an extreme step... be careful especially about your safety.

on a totally unrelated note... i managed to (read flukely) finally take a decent coin pic of circulating coins with my cannon a530

[bruce61813]

Has anyone tried this method?

As was commented before, don't use electrolysis unless you have no other choice, and then Do Not Use Salt [NaCl]. The high current wi literally burn the coin, and also you do not need more than 6 VDC. Use sodium bicarbonate or sodium carbonate  [or mix the two 5:8 or even 1:1], It works slower and does less damage to the coin.

As to 'stickyness', that depends on what created it. Water alone will remove little, dish washing liquid or washing up soap, will safely remove normal grease, hand oils, and dirt. a soft cotton or microfiber cloth will not add scratches. Adhesives can be removed with ordinary cooking oil, or something like Goo-Gone [orange oil], but they need to be washed of with soap and water. I have been cleaning ancients for about 10 years and find that alkaline soaps are the best overall. Unless you run into lime based encrustations.

Bruce