Coin and Paper Money Collecting/proof sets with toning

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Expert: - 3/30/2009


Question
Hello Troy:

I have some 1999 proof sets (9 coins in each).  I store them in a closet in my air-conditioned non-smoking home.

I was distressed when I took them out recently and found that all the coins have toning.  It affects all coins (in both of the plastic cases from the mint).

This would seem to lessen the value, as I've read many collectors will 'pass' on coins with toning.

Or -- is there some remedy that reverses toning?  I doubt this, but thought I might as well ask!

Thanks,

Don

Answer
Hi Don,

I imagine you are talking about the blue sets (clad).  The coins are looking foggy.  Clad coins are very very difficult to conserve.  It just can't be done by a novice and will cost to much to do by a professional.  If they are silver sets (red) you have chance of conserving them.  Basically, this is a real bummer.  On top of this, Proof sets in general are generally depressed in the market place.  The only way to get max dollars out of these is by no reserve auctions on eBay.  And be sure to tell people the coins are foggy and give a good picture. Expect 20% to 70% of wholesale for each set.

Why did this happen - The 1999 Proof set is not air tight.  You can left the plastic up on each set.  The insert is not inert - the Copper/Nickel will start to react overtime with the insert.  If you leave near the coast or mountain regions you can expect problems.  Wide ranges in temperatures or anything below 65 or above 90 degrees can start the reaction.  You need to surround coins with Air Inhibitors to soak up moisture before it hits your coins.   

If you found this information helpful please nominate me for category expert in coins.  If coming through Los Banos, CA please feel free to look us up at Thoreson Numismatics.

Thanks for the question,

Troy Thoreson, aucpro.com  

Coin and Paper Money Collecting

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Troy Thoreson

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Please, no error coin questions unless your coin is dated 1955 or before. I can answer questions regarding all U.S. Coins, Gold & Silver bullion, including regular mint and proof issue coins and currency. Since 2009, I have been contributing to the Red Book, "A Guide Book of United States Coins", by R.S. Yeoman along with two other publications. I currently run two coin shops in California.

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I have over 30 years experience in Numismatics. I own two coin shops and have examined thousands of coins over the years. Please allow up to 2 business days for an answer. This is a free service and I am happy to answer questions - but please be patient and understanding of my time.

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My company is an authorized P.C.G.S. and N.G.C. dealer. I am a Life Member of the American Numismatic Association and California State Numismatic Association. We are also an authorized Whites Metal Detector dealership.

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I have written articles for Coin World and the Rare Coin Market Report.

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I have a certificate of completion from the American Numismatic Association on how to detect counterfeit U.S. Gold Coins and how to Grade U.S. Coins along with other certifications. I have a Bachelor of Science in Business with a concentration in Accounting and a minor in Computer Information Systems.

Awards and Honors
I am listed as a contributor to the Red Book, "A Guide Book of United States Coins", the Red Book, by R.S. Yeoman. I have been contributing to the Red Book since 2009. I also contribute to the Blue Book and the new Professional edition Red Book. I have many other awards and honors.

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My past consulting clients included eBay, Inc., Yahoo! Auctions, and the United States Postal Service. I have many other great customers and help all no matter their level of collecting.

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