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Help & Advice About Cleaning Silver Coins

 
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Author Previous TopicReplies: 13 / Views: 624Next Topic  
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115 Posts
 Posted 03/28/2021  08:31 am Show Profile   Bookmark this topic Add SuperPoacher74 to your friends list Get a Link to this Message
Good morning.

I completely understand that cleaning coins can possibly lower the value, so this is clear.

Last week I picked up 3 silver eagles, 2 of them had some black spots / stains. They all looked dingy.
So I wanted to experiment.
I took a Tupperware & lined it with aluminum foil & sprinkled the bottom with baking soda.
I gently laid the coins in & poured in HOT water & sprinkled more Baking soda on top.
It immediately started to fizz.
I let them sit for about 6-8 hours.
I gently removed them & rinsed them in cold water.

THEY CAME OUT BEAUTIFUL!!

I DID NOT RUB, POLISH, BUFF OR BRUSH THE COINS, they just laid in the water.

How can this de-grade a coin? They were soaked in water & Baking soda & thats it.
I have a few key date Morgans & Peace dollars that I would love to brighten up.
Now my question, will this very basic wash de-grade my coins?

Im no professional collector but I'm starting to put more time into the hobby & I'm try to learn as much as I can so please excuse my ignorance if my question is basic for some.

Thank you!

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 Posted 03/28/2021  08:43 am  Show Profile   Bookmark this reply Add ijn1944 to your friends list Get a Link to this Reply
A couple before and after photos--large and sharp--might tell an interesting story. Thanks.
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 Posted 03/28/2021  09:11 am  Show Profile   Bookmark this reply Add tdziemia to your friends list Get a Link to this Reply

Quote:
they just laid in the water.


Nope.
Their surfaces underwent an eletrochemical reaction in which the tarnished silver was chemically reduced back to elemental silver by the presence of aluminum and helped by the sodium ions from the baking soda.

I will be interested to hear the other responses. My guess is that you can get away with this type of cleaning for minor stains on otherwise sharp coins.









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United States
155 Posts
 Posted 03/28/2021  09:23 am  Show Profile   Bookmark this reply Add Numiscrat to your friends list Get a Link to this Reply
If "beautiful" means bright white only, then you might be correct, but...

The coins so treated must be compared to their original, untreated equivalents. Mint luster comes from the metal flow in striking and the die surfaces. Chemical etching to remove silver oxidation products or alternatively, deposition/reduction of metallic silver onto the surface does not produce the same effect. As an example over-etched (dipped to death) coins won't cartwheel (for the coins expected to do so in original condition) when held in the light.

Then there is the matter of circulated coins than have been "brightened up". I won't buy any coins that have been harshly treated that way, not even at half price. For me—a coin that has obvious circulation wear but has been made blast white from cleaning annoys me. It is kind of like presenting me with a rusted out car body that has had hardware store spray paint applied over the rust spots. The paint does not make it as good as new, and you ain't fooling me with it... There is no way to replace worn metal and original mint luster on a coin, so brightening a worn coin really is like trying to accomplish autobody work with spray paint alone. .

Before you take off treating your coins, you might want to study the differences in appearance between altered and unaltered surfaces. I cannot stress enough—bright doesn't necessarily equal right. Whatever you do, it cannot be undone. It is forever...

Here is another thought:

If you want bright white, sell your original surface key date coins and then buy cleaned coins as replacements. Depending on what you have and get, you might come out money ahead. Details coins are heavily discounted.

Edited by Numiscrat
03/28/2021 12:01 pm
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39516 Posts
 Posted 03/28/2021  09:23 am  Show Profile   Bookmark this reply Add John1 to your friends list Get a Link to this Reply
Not my area, but I think a micro layer of silver was removed.
John1
( I'm no pro, it's just my humble opinion )
Searched 5+ Million Cents Since 1971
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United States
155 Posts
 Posted 03/28/2021  09:46 am  Show Profile   Bookmark this reply Add Numiscrat to your friends list Get a Link to this Reply
BTW: Not trying to pick on you. Rather, I am trying to dissuade you from an irreversible course of action you might regret. I, too, have messed around with damaged bullion coins, such as mishandled ASE's or merc dimes that came through a fire. If those are damaged, then no harm done. They were destined for a coin dealer's melt pile anyway.

On the other hand, I have a nice unc 1935 Peace dollar with two or three little dark spots that bug me. But, knowing how attempting to improve something can really screw it up, I won't touch that one.

Seeing high grade original coins in hand and getting to compare those against altered surfaces was the best way for me to learn. I often did not know what was wrong with my earliest purchases until I added a really good original surfaces coin to my collection. I am envious of one of our members, Grape, because he started out working in a coin shop at an early age. It is apparent that his eyeballs have been educated very quickly from handling high grade coins that I seldom see in person.


Quote:
Their surfaces underwent an eletrochemical reaction in which the tarnished silver was chemically reduced back to elemental silver by the presence of aluminum and helped by the sodium ions from the baking soda.


Another chemist beat me to it....

I don't know about you, tdziemia, but I am always afraid that explanations veering too far into electrochemistry are forbidden under the family friendly rules of this site!
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 Posted 03/28/2021  09:54 am  Show Profile   Bookmark this reply Add dave700x to your friends list Get a Link to this Reply
If you want to try this on classic silver coins I suggest starting with a common date Morgan that would grade very low MS or even AU although I'm not sure if results from lightly circulated would compare to a mint state example.
1883-O Nut
Edited by dave700x
03/28/2021 09:56 am
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 Posted 03/28/2021  10:48 am  Show Profile   Bookmark this reply Add tdziemia to your friends list Get a Link to this Reply

Quote:
I am always afraid that explanations veering too far into electrochemistry are forbidden



I was thinking a few of us could get together and develop a battery based on that reaction. Best I can tell, you should be able to get as much voltage as a standard dry cell. You could carry the battery and a tarnished silver coin in your car. When your car battery dies, you pop the tarnished silver in your coin battery and use it to jump your car. Then pull out the blast white coin.
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United States
155 Posts
 Posted 03/28/2021  11:35 am  Show Profile   Bookmark this reply Add Numiscrat to your friends list Get a Link to this Reply
@tdziemia

Oh my goodness.... I can see the YouTube videos now.... I imagine it would take a few rolls of coins to achieve both high enough voltage (series connection) and enough cranking amps (parallel connection of several series in order to have enough surface area to pass that much current and dissipate the heat) to start the car. That would create an entire new class of PMD "error" coins on the market to explain. If that happens, you are expected to do a coop quality slide show to explain them all! Seeing how hard dryer coin diagnoses are for some to accept, good luck!
Valued Member
United States
155 Posts
 Posted 03/28/2021  11:56 am  Show Profile   Bookmark this reply Add Numiscrat to your friends list Get a Link to this Reply
Sorry, there were a couple of assumptions I made in answering SuperPoacher's question.

First, I was assuming that the key date coins might have some circulation wear evident. This is a function of me not being able to afford uncirculated examples of key date coins in popular series.

Two, key date coins are going to draw the interest of more experienced collectors who will be more likely to discern alterations and respond negatively.

If you were selling bulk silver to stackers who have no interest in numismatic value, then the cleaned coins are not an issue for them, from what a dealer has told me. They aren't going to pay extra for key dates, either, though.

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United States
288 Posts
 Posted 03/28/2021  7:54 pm  Show Profile   Bookmark this reply Add MisterT to your friends list Get a Link to this Reply
Generally any type of cleaning of coins is frowned upon at best and outright condemned by others and I certainly do not recommend it. It is interesting however that you can find slabbed coins with labels of "improperly cleaned", suggesting that the alternative could be properly cleaned? Indeed there are methods used to remove pvc residue and other harmful deposits such as an acetone bath without disturbing the original toning. TPG's have cleaned and dipped coins many times and charge a "conservation" fee for the procedure. Granted they are not scouring them with harsh abrasives though or treating them with baking soda or vinegar.
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 Posted 03/28/2021  8:59 pm  Show Profile   Bookmark this reply Add Sap to your friends list Get a Link to this Reply

Quote:
It is interesting however that you can find slabbed coins with labels of "improperly cleaned", suggesting that the alternative could be properly cleaned? Indeed there are methods used to remove pvc residue and other harmful deposits such as an acetone bath without disturbing the original toning. TPG's have cleaned and dipped coins many times and charge a "conservation" fee for the procedure. Granted they are not scouring them with harsh abrasives though or treating them with baking soda or vinegar.

"Proper cleaning", also known as "market-acceptable cleaning", is cleaning done that does not affect a coin's surface, cause a chemical reaction with the metal or oxides on the surface, or is otherwise undetectable. Using acetone to remove organic "goo" like sticky-tape residue would be an excellent example of this.

We tell new collectors and the general public, "Don't clean coins", because they're not very good at which forms of cleaning are "market acceptable", and which are not.

Quote:
How can this de-grade a coin? They were soaked in water & Baking soda & thats it.
I have a few key date Morgans & Peace dollars that I would love to brighten up.
Now my question, will this very basic wash de-grade my coins?

There is admittedly some debate about the market acceptability of removing tarnish/toning from silver coins. A single treatment of a small area is likely to be undetectable, and thus "acceptable". The problem with coin cleaning is that it does not violate the Second Law of Thermodynamics: Entropy is maximized, also translated as "you can't unscramble eggs". Specifically, the chemical reaction that takes place in the silver-aluminium-baking soda deposits metallic silver back onto the surface of a coin, but does so randomly - it does not reconstruct the original surface, because the chemicals have no memory of where that original surface used to be.

This creates a surface that is "activated" - it has a higher surface area, at a molecular level, than an uncleaned coin. This, in turn, means that it is likely to reacquire toning/tarnish much faster than an original, unaltered surface. Which means you'll probably want to clean it again... and again... and again. I've seen this happen with my mother's silver spoon collection: the ones she regularly takes out to polish always tarnish faster and generally look worse than the new ones she's never touched, even under identical storage conditions. Cleaning a coin is thus like taking an addictive drug: once you start, you want to keep doing it, and stopping is much worse than if you'd never started. And if you do this baking soda trick to the same coin multiple times, you will end up with a coin that looks visibly worse than an uncleaned coin, dull and lifeless.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis
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 Posted 03/28/2021  9:42 pm  Show Profile   Bookmark this reply Add tdziemia to your friends list Get a Link to this Reply


Except it's not a baking soda trick. It's an aluminum trick (it's the aluminum that reduces the silver compounds back to elemental silver). You could also do it with magnesium or zinc, but most of us don't have magnesium foil in our kitchen.
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 Posted 04/17/2021  09:51 am  Show Profile   Bookmark this reply Add just carl to your friends list Get a Link to this Reply
Similar results can be obtained using Jewelry cleaner from Walmart. Or a wire wheel. I wouldn't use them though.
just carl
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