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Black Spots On Copper And Silver Coin

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Pillar of the Community
Canada
736 Posts
 Posted 03/31/2021  09:58 am Show Profile   Bookmark this topic Add silviosi to your friends list Get a Link to this Message
To all of this forum:

For long time I want to compile this extract from the McGill medical school course of Chemistry of the organic and amorf oxidation

Carbon is not involved in these surface finish anomalies and the process is not oxidation (so often described as the chemical
process). The culprit is sulfur and the process is sulphatization.

Carbon spots are found inside diamonds [inclusions from imperfect pressure during formation millions of years ago] ? not on the surface of coins and medals. The proper term in
numismatics should be ? SULFUR SPOTS.

These dark brown to black spots appear on both copper (including bronze) and silver coins (including silver clad).
These are formed, not with contact with carbon, but contact with sulfur from the environment. The sulfur comes from any variety of sources. The curing of rubber, for example, includes
sulfur by vulcanization. Thus rubber should never come in continuous contact with coins and medals.

Sulfur is also used in some manufacturing processes of paper. This is why coins tone in certain paper envelopes. Anti-tarnish tissue is made without any sulfur at all.

Sulphatization is a greater problem for the field of frescos than coins and medals. Here a sulfur atom replaces a carbon atom, physically changing the plaster UNDER the pigments of the
paint. In numismatics at least our sulfur problem is on the surface of the metal, where it can be treated.

More evidence is color. When carbon reacts with copper ? as copper carbonate ? the resulting substance is blue-green! Not brown-black.

Here is an experiment you can do yourself to prove the villain is sulfur, not carbon. Take any uncirculated coin, bronze or silver. The commonest source of sulfur for most people in
daily life are elastic rubber bands where sulfur was used in its manufacture. Place the coin on top of the rubber band so it stays in physical contact undisturbed for weeks at a time.
After months you will see a black line where the continuous contact was made, the sulfur reacted with the copper or silver to form copper sulfate, or silver sulfate.

Do something similar with carbon. Place in contact with an uncirculated coin any form of carbon ? diamond, coal, pencil lead ? and leave for the same time. Nothing will happen!
Try to speed up the chemical reaction by introducing oxygen, water, heat, pressure or whatever. It will still yield the same result, nothing.

In the finishing of high relief medals, as applying a ?French finish,? sulfur is the good guy. An active chemical containing sulfur is used to purposefully apply a darkening to the surface
of bronze or silver medals. With the use of ammonium sulfide this takes place in seconds! Medals totally immersed in this chemical must be withdrawn within ten seconds and immediately
washed with water to stop the chemical action!

Thanks for the patience to read. I do not know who wrote this or any kind of copyrights. It is a part of our studies materials in that time.
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 Posted 03/31/2021  11:52 am  Show Profile   Bookmark this reply Add okiecoiner to your friends list Get a Link to this Reply
Are you saying that a silver coin or grandma's sterling silver will NOT oxidize or tarnish or get dark spots in the open air, as long as it doesn't come in contact with Sulphur or rubber? This is news to me.
Pillar of the Community
Canada
736 Posts
 Posted 03/31/2021  12:47 pm  Show Profile   Bookmark this reply Add silviosi to your friends list Get a Link to this Reply
They are many elements who can tarnish the silver, but not black spots. A simple touch of the hand can make in time black traces due to the human sulfuric acid in our body. This is black. The tarnish in general has a blue reflection which is another thing. For these blue reflex of the tarnish we work now in my laboratory. We have 5 different composition from 5 different location, this it is not establish now.

The black spots is sulfur which is omnipresent everywhere in our environment. It is in water, in earth, in our body or animals, in the plants essential, etc. Is equal with potassium (K) and sodium (Na).

In fact the gold and the silver do not have destructive oxides. Just surface. The copper, zinc, iron, steel and nickel has destructive oxides which popular we say rot the metal (eat)
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 Posted 03/31/2021  1:10 pm  Show Profile   Bookmark this reply Add purelywasted to your friends list Get a Link to this Reply
Thanks for sharing. So these black spots are Sulphur related?

Is it reversible?



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Canada
736 Posts
 Posted 03/31/2021  1:24 pm  Show Profile   Bookmark this reply Add silviosi to your friends list Get a Link to this Reply
yes they are reversible. Base on my test the only problem I have is that under we have the metal on initial colour and the rest already changed. Probably our tests will success to brink everything correct.

In the case of silver is no problem. Very soon I will post the right concentration of borax and boric acid to be boiled in and the best soft soap to be use accessible to anyone.
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 Posted 03/31/2021  4:37 pm  Show Profile   Bookmark this reply Add okiecoiner to your friends list Get a Link to this Reply
I always thought that the term "carbon spots" had nothing to do with carbon. The term was used to just describe "black spots", not what the spots were made of. It is/was my opinion that the spots were mostly due to someone sneezing or coughing or getting a little spittle on the coin. I also would advise that you shouldn't advise folks on this site about your "best soft soap to use" in conjunction with boric acid or borax for use on coins. That's a no-no
Edited by okiecoiner
03/31/2021 5:02 pm
Pillar of the Community
Canada
1325 Posts
 Posted 03/31/2021  9:22 pm  Show Profile   Bookmark this reply Add 47P7 to your friends list Get a Link to this Reply
Okiecoiner, I am interested why Not?
if he found or has a solution that works, why not?
Would be interesting to hear from SPP as he also has some knowledge in that field.
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887 Posts
 Posted 03/31/2021  11:52 pm  Show Profile   Bookmark this reply Add JohnWayne007 to your friends list Get a Link to this Reply
Even if it were reversible, would it really be feasible? The way I see it is once you clean a coin with any kind of "Soft soaps" or chemicals other than pure acetone I doubt any grading company would straight grade it.

If there were a magic "AU to BU" coin dipping solution grading companies would probably go out of business because they don't grade cleaned coins and they would probably start getting a large volume of requests for coin grading after people cleaned them. If you don't care to grade your coins then you might be in the clear, but if you decided to sell your collection at some point in time the buyer might not like to find that his/her "MS" coin was once AU if he/she is the grading type.

Im sure the chemistry and science is there, and has been for years to clean coins in a safe way, but that still defeats the entire purpose of a grading standard, thus a solution of that sort will probably never make it into the hands of collectors IMO.

Long story short, once something foreign is on the surface, any attempt to remove it would throw the coin in a "cleaned" category, even if the soft soap 100% safe IMO.

PS. I don't grade my coins, and my grading skills are almost non existent but I'm sure my point was clear.
Aggressively searching Canadian Small Cents on a daily basis since 2018.

Some of my Discoveries.
1941 George VI 1 Cent DDO http://www.coincommunity.com/forum/...IC_ID=367977
1976 Queen Elizabeth II 1 Cent DDO http://www.coincommunity.com/forum/...IC_ID=373627
1970 Queen Elizabeth II 1 Cent DDR http://www.coincommunity.com/forum/...IC_ID=364301
1989 Belize 25 Cent's with a Doubled Die Reverse http://www.coincommunity.com/forum/...IC_ID=362747
Edited by JohnWayne007
03/31/2021 11:53 pm
Pillar of the Community
Canada
1325 Posts
 Posted 04/01/2021  11:56 am  Show Profile   Bookmark this reply Add 47P7 to your friends list Get a Link to this Reply

Quote:
Long story short, once something foreign is on the surface, any attempt to remove it would throw the coin in a "cleaned" category, even if the soft soap 100% safe IMO.

can anyone explain WHY TPG's do not elaborate on "cleaned" or "details". Like, give a reason, not just because it looks like it. I have submitted coins that came back as cleaned. However, the 50 cent piece was in the owners pant pocket until he took his last breath......cleaned & polished came back! (Canadian TPG-starts wit C) yes cleaned and polished by normal friction, 60+ years in some person's pocket.
Edited by 47P7
04/01/2021 11:59 am
Pillar of the Community
Canada
4707 Posts
 Posted 04/01/2021  12:16 pm  Show Profile   Bookmark this reply Add john100 to your friends list Get a Link to this Reply
The US big two TPG does it right by using just the two terms without a numeric grade, everyone now knows it"s a problem coin, there no need to add long comments of how a coin was cleaned, in my opinion it is a lot better than ICCS grading a cleaned coin with a numeric graded, a MS 63 cleaned is not a MS 63 coin
Pillar of the Community
Canada
736 Posts
 Posted 04/01/2021  8:18 pm  Show Profile   Bookmark this reply Add silviosi to your friends list Get a Link to this Reply
I thing that every one has a good point and reason.

My question is if a cleaned stamp or banknote by non invasive procedure are graded. Why the coins come back with NO grade except for those cleaned and "preserve" by the TPG him self for 20$?
Pillar of the Community
Canada
887 Posts
 Posted 04/01/2021  8:54 pm  Show Profile   Bookmark this reply Add JohnWayne007 to your friends list Get a Link to this Reply
I know that some TPGs offer services that "preserve" the coin but I think the logic is, as long as THEY are the ones to do it and put it in a slab, they don't expect it to ever leave that slab. But guaranteed if someone requested the preservation service and removed it from that slab a few years later and had it graded by a different TPG it would come back as cleaned.

Usually, if you are willing to spend the money to get a coin graded and preserved, it is because you never plan on having it removed from that slab.

Edit: Also to add, I'm pretty sure even if you did get a TPG to "preserve" a coin, it would be labelled as such, which would probably just be a fancy way of saying "professionally cleaned" which is not desirable in my opinion.
Aggressively searching Canadian Small Cents on a daily basis since 2018.

Some of my Discoveries.
1941 George VI 1 Cent DDO http://www.coincommunity.com/forum/...IC_ID=367977
1976 Queen Elizabeth II 1 Cent DDO http://www.coincommunity.com/forum/...IC_ID=373627
1970 Queen Elizabeth II 1 Cent DDR http://www.coincommunity.com/forum/...IC_ID=364301
1989 Belize 25 Cent's with a Doubled Die Reverse http://www.coincommunity.com/forum/...IC_ID=362747
Edited by JohnWayne007
04/01/2021 8:58 pm
Pillar of the Community
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3570 Posts
 Posted 04/01/2021  9:13 pm  Show Profile   Bookmark this reply Add okiecoiner to your friends list Get a Link to this Reply
You can't clean or preserve anything by a "non-invasive" procedure. By definition, it HAS TO BE invasive with something coming into contact with the object. If you are contemplating getting into that line of work, you'd better contract the TPG's to get their take on it and it won't be a 'kind" response. "Cleaned" is "cleaned" regardless of how it's done and the result is a "detailed" coin and money down the drain.
Pillar of the Community
Canada
736 Posts
 Posted 04/01/2021  9:42 pm  Show Profile   Bookmark this reply Add silviosi to your friends list Get a Link to this Reply
This it is the point. I had a pocket 10$ 1914 gold coin which was tarnish. Was a BU in my opinion and clean by goldsmith non invasive method. Come back NGC 63 Hoard, PCGS 64 hoard, ICCS 64 and CCCS 63. Can someone understand?
Pillar of the Community
Canada
1200 Posts
 Posted 04/01/2021  9:55 pm  Show Profile   Bookmark this reply Add purelywasted to your friends list Get a Link to this Reply
There are degrees of cleaning, leave unc coin on shelf, dust gathers, rinse with distilled water, technically cleaned, should it be labeled as such?

Vs.

Old coin scrubbed with sos pad to a shiny silver. Is it the same cleaned as dust and distilled water?

Personally, I think not.

I look forward to hearing about this method.
Pillar of the Community
United States
3850 Posts
 Posted 04/01/2021  10:33 pm  Show Profile   Bookmark this reply Add jimbucks to your friends list Get a Link to this Reply
Planchets are cleaned prior to striking so all coins have been cleaned.
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