Uncirculated Mint sets question.

I just recently baught 2 uncirculated mint sets, 1968 and 1969. Everyting is there, envlope, cardboard protectors and all the coins sealed in cellophane. All the coins look nice except for the 68 Kennedy half. its got kind of a frosty look to 3/4 of it. Was the cello not enough to protect it from doing that? I mean the coins still look great of corse, just that one has that frosty glaze. Feedback would be exceptional. :thumb:

 

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Well something happened to have the coin's metals to react. Logically, probably the set wrapper .

 

Frosty can be good. Can you post some good photos?

 

It may be from being improperly stored.

-LTB

 

The inside of the cellophane is lined with PVC and this is not a stable enviroment for coins. If you'll look closer at the '68 cent you'llsee it even has small black carbon spots on it. I'm coming to believe all of these sets will need to be destroyed and the coins stabilized in acetone/ isopropyl alcohol. Rinse them in warm water after a two day soak and gently pat dry.

 

This sounds disturbing......

 

It's a new one on me, too, and not all of the Lincoln cents have carbon spots, either! The packaging the Mint uses, even today, is not completely impervious to changes in temperature and humidity. It may just be some haze which is not unusual, but not necessarily harmful.

Chris

 

I've not heard that either. Since the coin supposedly was kept in the mint's sealed packaging, doesn't leave much else to point a finger at. What the op is attempting to describe quite possibly may be " Milk spots " which they hadn't noticed on the coin before , storage . A picture would be greatly appreciated . I'm inclined to agree with cpm9ball .

 

These sets are composed of four layers of plastic and the inner two contain plasticizer.

This was especially bad on the '68 and '69 sets but will eventually affect all the sets until 1985 probably when they went to two layers of a stiffer plastic.

 

These sets were not in hard plastic holders. They were in the clear individual compartment type mint packaging.

 

Please show us where you got this information. Inquiring minds want to know!

Chris

 

I'll attempt to get some pics up tonight. There isn't a single black spot on any of the coins. They all look great minus that one. And im 100% the packaging hasn't been tampered with. I'll get the pics up and we'll go from there. Thanks guys. Im really diggin this forum. lol

 

Look at enough mint sets and you'll see these delaminate. I think it's usually caused by exposure to acidic enviroments but am not sure. If you scrape off the inside and burn it you get the tell tale green flame. If the coins are pressed against the interior or there is excessive temperature change the coin will first become hazy and then start forming a mottled corrosion. If you stop this soon enough the coins can be saved but there's a point beyond which I can't bring them back.

Soak them in a solution of acetone and rinse in warm water. Remove the ones that are OK after patting dry. Then soak in a mixture of acetone and isopropyl or denatured alcohol. Finally whatever's left have to be soaked in mineral oil and then washed in detergents to remove the oil. 99% of the coins can be salvaged but I destroy a few inadvertantly in the process. Youhave to play around a little to find the right mixtures since the copper, copper nickel, and copper nickel clad require somewhat different techniques.

The '85 to date sets are probably OK. The '68 to '70 sets are awful. The '71 to '84 sets aren't too bad but a lot of the Ikes (being heavy I guess) are showing some trouble. Perhaps storing them on their edges will delay the problem. There are some specific problems in the later sets like the '84-D cent is terrible. It's barely even 25 years old and half of these are bad already.

Frankly the whole thing makes me sick to my stomach. I've got several of each date that were selected just because every coin in them is a gem and I'll probably end up having to cut these and stabilize them as well. The day of a ready supply nice clad available cheaply is coming to an end whether there's any demand or not.

 

This is most unusual.

I've not seen a '68 penny without carbon spots in many years in the mint set packaging. 95% of these are just terrible and most unsightly. The remaining 5% look nice at a glance but always have carbon spots on the obverse, reverse, or both. Typically it's on one side and usually the obverse. They can be quite small at first but they grow if the coin isn't stabilized.

 

I should mention that the 40% silver halfs are usually the first coin to get hazy. These tend to be more difficult to restore too.

 

I just don't know.

But I do know that these are four layers of plastic with two on each side of the coin. The two inner layers are very very soft and thin.

 

wow, im in trouble then cause i don't have a clue on how to do any of that stabilizing stuff. I guess there is no need to post the pics then. oh well, it wasn't an expensive venture thank god.

 

We would still appreciate the pictures so we can at least see what your seeing. Pictures would be very helpful.