How to Tone Coins

I appreciate the gentlemanly way you frame your comments. I can learn from you so I don't get a "time out" again. Further more, I don't wish to write about another different coin right now.

I wish you would allow me to insert my comments in color into your quote as it saves me time. Nevertheless:

Corrosion starts as a chemical reaction on a surface. Much of the time, the byproduct (think of rust) builds up in layers ABOVE the original surface (as on your coin) as the reaction continues. Additionally, the original surface at the point of the corrosion is etched away. In many cases, when corrosion is removed from the surface, only the pitting remains. Think of a "porous" Large cent.

Your OP coin is FULLY STRUCK with no weakness. A black color on most coins is a POISON and usually indicates oxidation that has gone so far as to be unattractive and damaging to its surface. IMO, that is the obvious case with your Large cent.
My mind is still slightly open - the thickness of a hair. Hope you can take a sharp image. BUT if you'll agree the black area is raised, I see no way to change my opinion.

I'm going to look around here for some corroded copper to photograph but at the moment our safes are closed.

 

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Could only find one in silver. Note the raised silver-black corrosion on this 8 rls is similar in color to the "die chip" on your OP cent.

 

"since coin cleaning is such an exasperating topic although I enjoy its discussions."

you are a very brave man to broach coin cleaning here. congrats.

coin cleaning AND coin grading then we'll have a real "exciting" discussion. LOL!. . . . .

 

Here's an idea...send @Insider that large cent and have him "conserve" it.

 

That's a good one! IMO, no conservation professional at any TPGS would attempt to improve that coin. I would not touch it either - it is gone. I would sell it or trade it + cash for a nice one.

 

I agree , Mikes been good for the hobby , and a lot of us have put a coin in a manilla envelope . A hairlined coin or one cleaned with baking soda will always be a detail coin and never will be straight graded . But someone who wants to drive a man from a hobby is just plain mean hearted . Disagreement is fine . Remember what goes around comes around .

 

Sorry...those short naps are great... We have mentioned polar and non-polar solvents, but within organic solvents, there are aliphatic and aromatic solvents. Each of these is better at dissolving some substances than others. An aromatic solvent has the presence of a benzene ring while an aromatic solvent doesn't. Benzene is out as a solvent (although as an undergraduate we used it extensively) because it causes cancer. Toluene is good, but many object to the odor and it evaporates fast. Xylene (BTW...Benzol, Toluol and Xylol are the same stuff) evaporates more slowly and therefore has less odor, so it tends to be the solvent many turn to.

 

If he wants to sell it, I would buy it depending on the price.

 

Actually, I always thought a coin treated with baking soda would show obvious evidence of cleaning. Actually, this is NOT ALWAYS THE CASE. I never would believe it but I have seen the technique demonstrated on specific coins in specific grades and I have examined the coins using a stereo microscope and could find no hairlines or evidence of treatment! I steadfastly still believe this is impossible but it will be one of those things that is true in spite of what I believe.

 

You may not know this about me, but I am a chemical engineer who develops high pressure systems for the petrochemical industry that are deployed all over the word in some of the harshest environments on the planet. Much of my job is calculating and studying the rate of corrosion of materials when exposed to certain chemicals/environments. I have written papers on the subject that have been published and some of the worlds largest companies come to me for advice. I know what corrosion is, how to speed it up and how to prevent it perhaps better than anyone on this forum. When I say that the spot isn't corrosion, you can take that to the bank.

I'll try to get a better image for you when I get home, but I would have thought that you would be familiar with die chips and the fact that they are raised off of the surface of the coin.

Edited to add images though I don't think that they will help very much. I warned you that my photography skills sucked. All I have is my phone and a single lamp. The detail I tried to take through a loupe, but it sucks too. The color here is much more like the coin in hand, but the dark areas are actually blue and violet in natural light. I suspect that this coin was cleaned then stored away in a sulphur laden atmosphere.

 

That's amazing... based on your posts and obviously unoriginal Cent, you came across as a well-off senior collector with money to waste that I was trying to help. Now I feel I have wasted all this time posting here.

If I were in your place I should NEVER have revealed you knew anything about chemistry or corrosion. As a chemist, you should know that corrosion products are often raised on a coin! Did you bother to view my image that contradicts everything you (as a chemical engineer) have stated? I cannot wait to see the micrograph, apologize to you, and regain my faith in whatever college you graduated from.

And furthermore, I hope you share more of your knowledge about speeding and slowing corrosion on coins.

 

The images are perfect! The highest magnification shows no build up next to the "U". However, the tilted photo shows a corroded build-up on the surface and leaves. Based on the "U' and total photo I should be more careful when viewing photos because this coin does not not deserve to be called corroded, and blue surfaces indicate acetone or cotton. So shut my mouth I STAND CORRECTED.

I still don't see the "die chips" at 7 o'clock as none are listed for N-4.

Finally, will you agree with me that corrosion products can be raised on the surface of a coin?

 

If that coin could be stripped and re-toned, that would be a good thing...attractive coin.

 

High mag photo shows "dead" surface by "U". IMO, best not to touch as plenty of folks will think it is a beautiful original coin.

 

Nah, it's actually a quite attractive coin in hand, but at the same time obviously tampered with. That doesn't make it uncollectable to me at the right price. I will agree that there are some instances that corrosion can be raised off of the surface, but this is not the case here. Out of principal I won't advise any means of speeding up the process, but the info is out there. For preservation, seek Doug and Jims posts out and you will discover a treasure trove of information. Good discussion @Insider, I'll be back when I can provide a better image of the surface of the raised area in the field as soon as I can.

 

Do we know what sort of oxidation it is?

 

@kaparthy, you posted this a few days too early. Today is Monday. April Fools' is Friday.

 

I didn't know that . I remember when I got back into collecting after many years off , the 1st VAM book said to clean coins with a baking soda solution . Well like a dummy I took their advice and ruined a fairly nice SLQ that was too dark to see . It peeled that luster right off . I'd still like to see one that kept it's luster though .

 

The only "questionable" raised area I originally saw on your coin was an "image artifact" (see tilted coin photo w/raised black areas) that do not exist on the actual coin. The die chips on the coin's obvers are on this variety and were of no concern to me at all. The "black" color in the original photo is what looked like corrosion and I am satisfied that my observation was wrong.

I'll look forward to another discussion sometime again. Now can I get you to say there are "many" instances of raised corrosion products or am I pushing the limit.

 

Fluff:
1. to pat a pillow in an attempt to make it appear more desirable.
2. To wax a jalopy to make it appear more desirable.
3. To tone a coin.............