How to Tone Coins

Toning is chemistry. The silver or copper in the coin reacts with sulphur in the environment. "Artificial" toning (so-called) is often applied to coins to hide defects that would deny the coin a high Mint State grade. Proper re-toning is just conservatorship, returning a coin to a more natural appearance after uncalled-for cleaning.

While silver does react with many other elements and compounds, the most common toning results from interactions with sulphur. You can buy sulphur in 50-kg lots from Fisher Scientific and other sources. Mix some of the powder with petroleum jelly ("Vaseline" brand, for example) for easy application to the surface of a coin.

You can achieve similar (though unpredictable) results from burying a coin in cooked cauliflower or cooked egg whites. (I got stunning "champagne blue" from cauliflower.)

An interesting interaction comes with iodine. Tincture of iodine applied to a harshly-cleaned silver coin renders the surface flat gray. With 19th century British sterling and ancient Roman and Greek issues the result can be pleasant to the eye.

Of course, results vary. If you do not like what you got, clean the coin with baking soda and start over. And, of course, never, ever, ever do any of this with a coin that is truly uncirculated.

Understand that while silver can turn nice colors, copper usually just turns black. Sometimes you get better outcomes. It just depends on the coin.

 

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Here, you dropped this little metal ball thing. Thought you might want it back.

 

The premium for a nicely toned coin is largely because an astute collector will recognize a coin that has not been tampered with (and appreciates the toned look). Though idiot eBay bidders will pay a premium on a coin that has been tampered with, I will not and can easily tell the difference.

 

Really @kaparthy like there aren't enough people ruining coins already. I just lost a whole lot of respect for you.

 

Any form of artificial toning is coin doctoring, pure and simple. Your statement that AT will hide defects that could deny a coin an MS grade clearly, to me, shows a deceitful aim.

Frankly, I think you may have posted just to see what you can stir up.

 

I have a Silver Eagle that I kept wrapped up in a old Chinese note. Its been about 2 months now and its starting to tone,albeit a gold tone,but it is toning nonetheless. I know have it on a piece of oak by my window sill

 

I'm going to leave this here as a Google Search result:

Michael Marotta publicly advocates artificially toning coins.

From this moment forward, Mr. Marotta, one of my numismatic goals is to see you driven from the hobby.

 

While I disagree with promoting the artificial toning of coins, some of your guys reactions seem overly severe. Everything posted is already well known to the types of people that AT coins for malicious intents. I think his intention was informational towards people that would like to tone some coins for their own enjoyment. Of course the end result is the same regardless of the intention, but damn, you guys can be brutal

It's also kind of a "snake eats its own tail" situation, as with counterfeits, where learning the process for how it's made also teaches one how to identify it. Double edged sword.

 

Coming without any sort of caveat regarding the lack of acceptance of artificial toning by the numismatic community at large, from a person with a widely-known name in the hobby, and expressed as an unconditional endorsement of the process as "proper conservation"....

He even advises employing baking soda to undo the results if you don't like them.

No. Not now, not ever, not acceptable. Very little in numismatics is black and white - we all know that well - but this is. It's a troll post, plain and simple, with the effect of misleading newer collectors into thinking his ideas are accepted practice. Whatever goodwill he's ever engendered has been completely undone in one fell swoop.

 

I think Mike was yanking some chains and boy some of you took the bait........

 

Swallowed it right up.

 

We may have. I suspected that when I answered. But calling AT legitimate "conservatorship" required a response. If he was being purely satirical, he missed the mark.

 

Who the edited is Michael Marotta?

 

Most dealers will pay premiums for coins with original surfaces, and deeply discount or even decline to purchase coins that have altered surfaces.

 

When I tell people I invented a great copper cleaner I get all sort of responses so I normally just sell my JPL Coin Care to astute collectors since coin cleaning is such an exasperating topic although I enjoy its discussions. Having said that here is a good story... When I collected NJ Coppers and as some of you know I put together one of the great collections that sold in Stacks in 2008 (Americana Sale). One of the rarities in my collection was the Maris XXX. One of a dozen known and somewhere in the middle of the CC. The coin originally purchased was ORANGE and was harshly cleaned. So what to do? Anton and myself developed a process to strip off a micro-layer of the copper and then let the coin naturally tone back. After the stripping operation the coin was placed in a sulfur envelope for around SIX YEARS whereupon with just a touch ALSO of a common hair sulfur ointment was dabbed in the inside of the flip and eventually after more than a half decade later the coin came partially back with a olive brown color (i.e., natural tone).
IMO we brought back a great rarity to its original surfaces - others may say it was just profit orientated ... so the lesson here IMO ... if a coin that has been cleaned or dipped perhaps trying to bring back its original color its not such a bad thing. Agreed surface hairlines or light scrubbing is something all together different.
Coin conversation or trying to undo the stupidity of others is OK IMO. Also some coins just unfortunately are exposed to the environment in unfortunate circumstances as was this M XXX NJ Copper.
I have used aluminum foil wrap on silver coins in an electric oven for 15 minutes at 400*F. More time - more toning - but again usually just for dipped coins so the copper can react and bring the coin back - again you can never get that CARTWHEEL EFFECT back but again for me this is coin conservation if I am stuck with a clean coin or if I feel I can bring a coin some new life.
Just an opinion ... after the sale I did notify the buyer of this coin who did not mind the intensive conservation that went into this rarity ... just for the record.

John Lorenzo
Numismatist
United States

 

after the sale?

 

The coin was described as partially olive toned and cleaned recently as the coin was also pedigreed to the sale where it was described as ORANGE ... in the Stacks cataloging. The new owner did ask me the process after the sale.

 

While I can agree that you may have made the coin look better, you cannot claim to have brought it back to its original surfaces that has forever been destroyed by whomever decided to clean it in the first place. Just because a TPG decides that the coin is market acceptable doesn't mean that it has not been tampered with. Would the same thing he true if a holed coin was filled so nicely that it was undetectable?

 

He's the quarterback on the Tennessee Titans.

 

If a hole's filled in a surface, and no one can see it, did it make an impairment?

We are, in the end, discussing physical processes here, and as far as I know there are no psychic traces attached to a coin that capture the intent of people manipulating it. That's why I think the whole natural/artificial toning fight is ultimately futile. In fact, I imagine I'll see a day when toning indistinguishable from "natural" is commonly offered as a service. I have my own ideas what that will do to the market.