Do you Consider a Dipped Coin to Be Cleaned?

Passivation certainly happens with some metals (and oxidants); that's why we can boil water in aluminum pots without the water attacking them, and why we can handle fluorine with nickel piping.

On the other hand, we have things like bronze disease, which is definitely autocatalytic. If you don't get rid of it, it'll spread.

I don't think silver sulfide is autocatalytic, but I'm pretty sure it's not passivating -- otherwise, there wouldn't be the worry about toning "progressing to the terminal stage".

I'm still very much in the learning stages, though. (And I hope that never stops!)

 

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This is really not true, especially for BU Bronze coins. Quite easy to tell if they have been dipped, MS70'd, or any number of other treatments.

The reality of discovering an altered surface coin is not to look at the coin and say "this coin has been dipped", but to look at it and say "this coin is original". In other words, it's easy to say if a coin has original surfaces. If it does not, then it has been tampered with. I can tell with 95% certainty on BU Bronze coins. I am not so well-versed on Copper, and even less so on Silver, but there are folks who can tell you with >95% certainty on these. Circulated coins of all metals are a different study and may be less certain with more variability.

The problem lurking in the background (or maybe the gorilla in the room) has been alluded to...it would not be a wise move for Numismatics to suddenly become aware of the coins that have been altered in some way. Of course the damage this would do varies by series. As has been said previously, most 19th century coins have been altered, so it is very difficult to find a coin with original surfaces. This is known by the collectors of these coins, so they are traded with a "wink and a nod". The damage would vary by series and specialty, with many folks not caring, while others would eschew any altered coin. Original coins would spike in value, while altered coins would drop precipitously.

 

There isn’t anyone who can tell you if a silver coin has been dipped or not at the 95 percent confidence level unless you’re talking about heavily worn coins which should have never been dipped in the first place. Some people may think they can but they really can’t. It’s just a guess based off color or an assumption unless they were the one that dipped the coin or some record of that happening exists

 

Actually, it is the "uncertainty" that maintain's the coin's value. If an experienced collector "knows" a coin has been dipped, then if a new collector buys that coin from him and asks "has this coin been dipped", what does the collector say? Does he say "yes"? He does not, because he does not really know, and if he says "yes" the sale will not happen. Does he say "no"? Maybe, but he can't say it with certainty, and indeed if he "knows" the coin has been dipped then he is being intentionally deceitful. Does he say "I don't know"? That would be the most honest answer, but one that would put him out of business fairly quickly. So he say's "no", or if the coin is slabbed he says "not according to PCGS/NGC because they slabbed it". Business continues because this obfuscation leans on the actual uncertainty this collector has.

 

It's actually not that difficult. Do you have a stereo microscope? Can you take a good picture of a coin with accurate colors? It just takes experience.

 

It actually is that difficult that’s the entire point. People convince themselves they’re these unfoolable experts that can somehow say everything that’s happened in the 100 to 200 year history of a coin, guess what they can’t.

Unless someone just collects heavily circulated coins pretty much everyone has coins that have been dipped before in their collections. And there’s nothing wrong with that since they can’t tell when it was done properly

 

Your comments suggest that PCGS and NGC don't condone dipping coins. Your statement couldn't be more wrong. Not only do they consider it an acceptable practice...they do it themselves.

 

This is inaccurate. Proper dipping of a coin should leave no evidence that it has been done. If it does, the coin has been improperly cleaned and is damaged.

 

I never said that. What I said was that the person selling the coin might say that in order to create uncertainty.

This is a common misconception, propagated by folks who either dip coins or condone dipping coins, or perhaps folks who own coins they know or suspect are dipped and want to believe they have not been damaged. Dipping leaves visible evidence that shows itself under a microscope. Even a single, quick, "harmless" dip does visible damage.

edited to add: I must admit that I may not have as high a success rate with early Lincolns, as I have not studied them enough. The die preparation was different for these versus later years, and colors seem more variable. If I used my general criteria on them I would end up concluding that most of them have been altered. Of course this may be true, but I have not studied enough known-original coins to be sure.

 

Properly dipping a coin in no way damages a coin. Period...end of story. This is the standard of view of numismatists worldwide and has been for decades. While your personal opinion may differ from this...which is fine...to suggest that anything else is a standard view in this field is wholly inaccurate and misleading.

 

Exactly. Unfortunately conversations with subjects like these almost always turn into soap box arguments where someone always comes in Abkhazia how superior they are and they can tell everything because they’re more experienced ect. It of course isn’t true but they believe it to be and no one will convince them otherwise.

 

Perhaps so, but that does not make the "standard view of numismatists" correct on this point.

I find it very telling that folks are so adamant about this. Seems to have struck a nerve. Folks don't like to hear their coins have been damaged, and may have actually lost value rather than gained it through altering the coin surfaces. Imagine what would happen if I published an article that described exactly how to determine if a coin has been altered so that anyone with the proper equipment could do it. I can see why there is such an uproar!

Yep, discrediting the messenger is an excellent obfuscation technique, though a bit transparent.

 

If you published an article on it I’m sure it would be proven untrue just as your comments on the subject have been so far

 

So many rely on TPG's to evaluate their collection. I have yet to see "Ugly" or "Terminal Toned" written on a slab nor have I seen "Original Surfaces". I take that as those are a given for a graded coin. But, there are multitudes of "Cleaned" or "Altered" slabs. I've never seen "Conserved" on a slab either, maybe you guy's should protest and get this changed.

 

The uproar that you claim you've created (which I honestly don't see) is because you have made completely unsubstantiated claims. Dipping has been a method of conservation for decades...it's widely accepted and considered normal. You claim that you have evidence that it is damaging that apparently has alluded the international community all these years...yet you have not provided any actual evidence. Just because you don't like it doesn't mean what you say is fact.

 

I suppose only way to prove it is to do a double-blind test. If you're willing we could find a 3rd party to take a group of coins (preferably Bronze Cents but Silver coins are OK as well) that are known to be original (perhaps from OBW rolls) and dip some of them and send them to me. You send the list of coins to a 3rd party we both trust. I inspect the coins and send my analysis to the 3rd party, who publishes the score.

edited to add: silly me, I made an error in the experimental design. We'd need the 3rd party to do the dipping and record which coins were dipped and which are still original.

 

The problem is...a coin that has been properly "conserved" (call it conserved, cleaned, dipped, or whatever you want) leaves no evidence. There is no way to tell. Sometimes you can infer that the coin was likely conserved simply due to the freshness of the surfaces verses the age of the coin (because coins are made out of reactive material)...but there is no actual evidence despite what some seem to claim.

 

It is widely accepted. But it also does damage. The dip will physically alter the structure of the surface - that's why doing it once or twice is okay, but doing it too much is damaging. And this has been known for decades.

For a scientific analysis, and proof of what you're looking for, read Weimar White's "Coin Chemistry." I don't agree with all his conclusions, but he makes a very compelling case backed by science.

Dipping is absolutely causing damage, and thus cannot be considered conservation.

 

I understand how dipping a coin works. It is a mild acid that removes a very small amount of the surface of the coin. But, a properly dipped coin will show no signs of this damage. Will show no signs of muted luster from removing too much of the surface.

Going back to what I said before...a properly dipped coin will show no signs that the coin has been altered. This is because the amount of material that was removed from the coin is so minimal. Was some removed...yes. But there is no way to tell.

 

What White shows is that if you weigh a coin before and after dipping, there will be a difference.

And what rmpsrpms is trying to tell you above is that if you use a microscope, you can look at the flow lines. Even after one "proper" dip, they will be affected.