It's been a while since I posted on this forum. I originally had this idea for a thread and posted on a tpg forum where I usually spend my time. Unfortunately it didn't last long. There was a discussion there several months ago about whether or not blue and purple colorfully toned copper is AT or if when coincare or MS70 are applied to the surface of UNC brown copper coin the surface contaminants or brown tone is removed to reveal the colorful blue and purple toning underneath. Some of the biggest names in copper coins were arguing on both sides so I bought some MS70 thinking I would experiment. The bottle sat on my shelf for months and I finally got around to it. I don't claim to be a chemist and others might be able to explain what is happening better than I can, but it seems to me that the MS70 is not applying any color to the surface, but reacting to certain surface toning to change the color. Some of the coins had no change other than to appear brighter, while others changed color completely. A member on the other forum suggested the color change is also reversible, but the thread got pulled before any explanation was given. My main goal is to start a discussion about whether or not this type of treatment is considered market acceptable(because there are many similarly toned coins in tpg holders) and also to gain some insight into what coins are supposed to look like and how different chemicals affect the coins.
Some coins look better to me in the before photos, some better in the after. Interesting experiment that I personally would not have conducted, so I am happy someone else dares to test the waters. I think some of the after-coins might pass TPG, while others would definitely not. Any chance you are going to take this test to the next level and submit to TPG?
I thought about it, but have not decided to yet. I think I have a couple of 1961 proof Lincolns I may try next week and add to the thread. The interesting thing for me is that the more toning on the coin originally, the more the surface color changes. The Red Lincolns lost some of the red, but only slightly changed color. The brown centavo(brass) and 20 centavo dramatically changed. The bu(brass) centavo didn't seem to change at all.
the real question is whether they would get tagged and bagged as questionable color by a 3rd party grader or they would get straight graded and slabbed....
You can go back 20 years on the NGC and PCGS forums and find posts/threads discussing this subject of MS70 and copper coins. Even back then, it was known, by virtually everybody that knew anything, that using MS70 could on copper coins could and would result in the coins turning some shade of blue and or purple. And even back then, some were slabbed but a great many more were not. And back then there was no such thing as problem coin slabs - there were body bags. Bottom line, using MS70 on copper was something that you just didn't do ! At least not unless you were trying to produce artificially toned coins so you could sell them for a premium. And the reason that worked was also simple. It was because copper coins sometimes toned those colors completely normally, naturally. As for the argument that it's not the MS70 causing this toning, but a reaction of the MS70 with something on the coin that causes the toning - WHO CARES WHAT'S CAUSING IT ! There's only one thing that matters - that it happens at all - and quite often ! If there is something on the coin that cause this, you have absolutely no way of knowing that before you treat the coin with MS70. And once you do treat the coin it's already done. So why risk it ? Simply do not do it ! Now can you reverse this, remove the color produced ? Sure ya can, if ya know how, but most don't know how. One way is to dip the copper, that'll take the color off alright. But then most folks are gonna pipe up and say - wait a minute you can't dip copper. Well, horse puckey ! You can dip copper, it's been being done for decades ! And the fact that there are so very, very many copper coins designated as Red in TPG slabs proves it. In point of fact there are more Red copper coins in slabs than there are RB or BR combined ! And yet copper is the most reactive of our coin metals - it tones faster and more readily than all other coins. And yet there's more red ones than anything else. The whole issue is most folks don't know how to properly dip copper, so they claim it can't be done because they can't do it. But that does not mean somebody else can't do it. Not only can they - they do ! And they have been doing so for decades. And the proof of it is right in front of everybody's eyes - but they simply can't see it because they don't wanna see it. It would ruin their perceptions of value regarding copper coins. And that's something they just can't tolerate. But copper and MS70 - I advise you not to do it. And there's no reason too. There are other methods to properly clean copper, that are just as effective, but yet do not risk turning the coins blue or purple. And the TPGs, nothings changed regarding this - some they slab, some they don't.
I should have added something else but forgot to do so. MS70 is a great product to use on clad, silver, and gold coins. Dealers and knowledgeable collectors alike have used it for many, many years on those coins when they are getting them ready to send in for grading. Why ? Because it often makes just enough difference to get them a grade bump. But use it on copper ? Unh uh, you need to walk away from that idea.
GDJMSP ... I have enjoyed your posts for years. This one was bang on! I have posted this thread on another site and we all speak from the same mouth. Great post!
So this is exactly what I mean. You state that for years everyone knew that MS70 would or could change the color of copper blue and purple. You also state that they sometimes grade the coins because copper coins will also naturally tone these colors. I’ve clearly shown that not all copper coins were changed the same with the MS70. The 2 one centavo coins are the starkest difference. The BU coin did not change at all and the coin that had toning which had formed and would be considered Brown changes dramatically. Did the MS 70 strip away crust to show colors that you state can happen naturally or did the chemical react to something on that coins surface and create a color that wasn’t there? The centavos are actually brass and both came directly from mint sets with no other treatment that I am aware of. It seems you are OK with properly dipping silver and even using MS 70 on silver. Why is that acceptable? EZest and MS 70 clearly alter the surfaces of silver. If you are in the camp that MS70 is creating a chemical reaction on the coin and artificially toning the coin then I can see why you think that is bad. I do too. But what my question to the masses is if MS70 is removing some kind of tarnish on the copper(exactly what dipping will do to silver)and the natural blue and purple colors are what’s left(colors that you state are possible naturally) is using MS70 actually conservation? It is my assertion that people don’t know for sure but they will argue to the death anyway. Depending on which benefits them. You ask who cares what is causing it. I say we should all care. I’ve seen enough toned copper in TPG holders that looks too similar to the coins I’ve just shown to believe that the TPGs don’t give MS70 treatments a pass. At least they have in the past. Edited to add that a similar statement along with photos from CoinFacts are what probably got my thread nuked in the other forum. I’m not here to advocate for using MS70 on copper or any other coins for that matter. I’m here to show people what to look for.
Might it have something to do with the specific alloy used? https://www.britannica.com/technology/bronze-alloy https://www.britannica.com/technology/brass-alloy
You are correct - you will see people argue this all day long. The truth is, we just don't know. I am personally very strongly of the opinion that the MS-70 is reacting with the surface of the coin and creating artificial toning. You'll see people argue that it's just taking off a layer and revealing something that's already there. However, look at the coins which reacted most strongly: there is not a single trace of blue or purple on those coins before. It is not taking something away and revealing existing toning - you'd be able to see some hints of it before the treatment. No, this is creating a reaction that wasn't there before.
I have always heavily suspected that shiny red copper coins from the 19th century must have been treated with something, but they look so great I just decided to ignore that obvious fact. So this thread confirms those suspicions, which honestly were 90% confirmed anyway, but now I know more about the process and the medium. I personally would avoid buying copper coins with bluish toning because I don't really like it. Now I have another reason to avoid them - it could be a sign of treatment. Another day, another thing learned.
Where's a research chemist when you need one? The MSDS lists the five ingredients... The metals of the coin alloy are known and the contaminant has to be fairly common (uncirculated coins aren't exposed to the same variety of environmental factor) (a degreaser, machine ool, residue from anealing, something like that)
When a cent is dipped, it doesn't really have a red color - it has a pink color. The dip is stripping the patina off the coin, and it looks unnaturally bright. It has to regain a patina to get an attractive red color. Something like EZEst, or any other coin dip, will do basically the same thing. MS70 works a little bit differently, hence the blue appearance we're seeing.