Is it true that cleaning a coin removes a surface film?

True it is not a film, but it is different from being a flat surface. This is a Morgan dollar (MS) surface magnified 400X , with a 'real' microscope , not a USB type. What you see are not seen with the bare human eye, even with a 30X loupe. They are caused by reverse indentations caused by finishing the coin die, so they are roughly triangular. This is what causes the "spinning wheels" effect when you tilt a Morgan back and forth. Also for people interested in toning, they also serve as refraction devices for the different wavelength of colors caused by chemical reaction.
If friction, wear, "restoring" wears down the peaks, the above characteristics will be reduced or disappear. the peaks are what are being called as "film"



On the Peace dollars, the finishing process produced very small ridges, so maybe a finer grit . You can see the difference below. This is the surface of a Morgan on left and a Peace on the right @100X.



The difference makes the "wheels" and toning effects less. IMO, Jim

 

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Don't make this hard. I have no idea of the references you mention but there is a lot of nonsense passed around these days.

A lightbulb went off for me when I determined that a PROPERLY CLEANED coin was one exhibiting NO EVIDENCE OF CLEANING while using my stereo microscope at the ANA's Authentication Service in DC. This definition (in red) was used from then on when answering collector's questions about cleaning. Hopefully, it will be continued to be passed down as is WITHOUT ANY UNNECESSARY MODIFICATION.

BTW, in a few cases (before becoming more knowledgeable) we called customers to get their permission to clean the gunk around mint marks on their coin so we could authenticate them. This was done using a stereo microscope.

 

Jim,

Thanks for making that correction! I agree. Original Mint luster is NOT a film of any type.

A "film" implies a coating of some type. I have never heard this word used in numismatics except to describe that effect. Early stages of oxidation can be described as a natural "film" that occurs to metal.

What you have shown are die radials. They give BU coins the cartwheel.

 

I have been around here long enough to understand the difference between improper and proper cleaning. I will refer you to Doug's explanations which can be found in a forum search.

 

You say stuck with - I say enjoying. I buy details coins pretty frequently, if the price is right and I want them. I don't have a huge budget and I'm not buying to resell, I'm just a collector, I buy what I like and / or what I need to put together or improve my collection. For example my newest 1921 SLQ - freshly back from ICG is a details VF25, but I bought it for a details price, and it's much prettier than the ANACS G4 I had in the slot in the collection. I love it! I also am trying to learn how to better identify raw coins that have been cleaned, I'm still not very good at, but my ICG submissions are teaching me a lot, as well as buying slabbed coins here and there from the other 3 major TPGs. Here are the ICG pics - because my pictures are usually terrible, even with my new iPhone (I admit I was hoping for a higher grade, lol, those who think ICG overgrades crack me up, as that is not my experience at all, I am always on the look out for ICG slabbed coins that PCGS snobs turn up their noses at).

 

That’s what I’m saying though.

If someone sold say a VF 1893S Morgan that’s been cleaned for like $100 I would buy it.

So it’s not necessarily that buying cleaned coins is bad. It’s all about price.

 

I wouldn’t buy a $100 93-S because it would be a fake.

 

If it was TPG certified and matched the photo associated with the cert number I would definitely buy it.

I think you’re assuming that all cleaned coins are priced too high but if someone can get a good deal on a cleaned coin it would make sense to buy it.

 

I think you’re living in a fantasy world. Yes if a cleaned 1804 draped Bust dollar in an authentic slab and photo matched was for sale for $50 I would jump on it. But that’s not gonna happen.

I’d also buy a scratched hope Diamond for $75.

 

The Hope Diamond may or may not be a fair comparison to make a point, snarky or not.

The Hope Diamond had never been formally graded in The U.S. until 1988, even though it had been in the U.S. since 1911.

The grading process revealed bruises and chips. There is a 1975 report by a noted grader that concludes the diamond had been slightly re-cut while in the possession of Harry Winston.

Diamond Doctoring? No formal U.S. grade for 77 years, yet owned by U.S. interests?
Scratches, chips, bruises, probable re-cutting? Don't buy that sucker.

My only interest in the history was the philatelic side, since it was shipped by Registered U.S. Mail.

Other than that, I know nothing about diamonds. That is why I settled for rhinestone for her Wedding ring. After all, nobody knows the difference if it was not formally graded, right? She has not caught on yet, so I figure this close to my personal trip into Once Upon A Time Land, I am good.

 

My point is...nobody is going to buy a legitimate 93-S Morgan in any condition for $100. That possibility of finding one is the same as finding a damaged Hope Diamond. If you do...it's fake.

 

I know, and don't disagree. I am not sure the member meant the $ quote as anything but hyperbole, though, which of course has a tendency to trigger a reply in kind.

 

When my mother was alive, I gave her a US gold coin for her charm bracelet on every occasion. The $3 was a beautiful BU counterfeit but she never knew it. One day she told me a man at her club offered to buy it for $1000 which was far below what a genuine was worth. I told her she should have sold it to him because it was a fake! Boy, was in the dog house for awhile until I replaced it. She also wanted to know if any of the coins in her other jewelry were fake. Lucky for me - no.

 

It all depends of the coin, the metal it's made off and how it has been preserved. Bronze coin's which has been covered 2.000 years in soil are in need of a different treatment compared to a 100 year old example made out of Gold.

Just purchased a RPC I 1467 type, it was hidden in French soil for many centuries, the more I look at these issues revealed by mother earth, the more I enjoy the 'imperfections'. Cleaning, no way.

 

I didn't see that anyone answered this question. The answer is no. Cartwheel luster is created during the minting process. When the coin is struck, the metal spreads from the middle outward, and that creates cartwheel luster.

 

Don’t let Doug see that! He makes a convincing case that the metal flows the other way, from the edge to the big voids in the center of each die.

In any case, the metal flow wears radial lines in the fields, since they are squeezed down more than the devices, being thinner. These striations reflect and scatter the light, having a big effect on how much luster a coin has.

 

Metal can flow in many directions BUT basically outward. That's why they are called redials. While some metal at the edge may flow inward at the same time to fill the legend, the planchets are upset to get the metal out near the edge in the first place.

 

Here’s a discussion of the inward / outward flow from a couple of years back.

How Worn Can A Die Be and Still Strike MS Coins?

 

I started to read the link above but I'm not going any further for now because I'm not in the mood. Judging from this post on the first page it will be a complete waste of time with lots of "misinformed opinions" that will only confuse folks who read it. At first I would ROTFL and then become very angry at the state of numismatic education in this country. Perhaps Doug had a different way of defining an MS years ago to make a point after I stopped reading.

Fact: An as struck coin is 100% mint state when it leaves the dies. Learn it.

There is a very simple way to confirm the actual direction of metal flow that can be done at any facility with a die and a press. Prepare a planchet and paint colored rings 1mm wide From the rim inward for 1cm. then strike the planchet and see where the colors end up. An aluminum planchet with anodized colored rings should work even better. This would make a valuable addition to the story of the minting process.

 

Not sure why anyone would disagree with this. Detail coins certainly do have a
"correct" or "fair" price, and a price at which they are a bargain.
Now, figuring how much to discount a problem coin is an art all of its own.