I see a haze is common on modern (post 1950) proof coins. They develop it from air of reacting with the original government holder. Other than the haze they look really good. Then I see proof coins with no haze in PCGS or NGC slabs. So is it possible some of the hazy coins were cleaned so now they look like new? Is there any way to tell? Does it matter as far as value of the coin? Thanks
The film type government package, as well as any cardboard or paper used, was intended for transport and not for long term storage. The materials were not close to air tight, and most were porous to reacting chemicals in the air or paper around them. Many proof sets were collected still in their ordinary paper envelopes which generally had a high sulfur content. The film material did not react , but did allow reacting substances to pass through, a possible source of any spotting of the coins. For areas of the country that are usually dry and not in high industrialized, chemically laden air, the coins would have the possibility of high unspotted survival, and those are probably the coins you see slabbed. "Cleaning" a proof coin of damage and not having it visible ( sooner or later) again is extremely difficult IMO, and would have to be done carefully. Jim
Yes it is possible to remove haze from Proof coins, and it can be done without damaging the coins. The product MS70 does a good job of this, but don't use it on copper. And if you know what you are doing, you can use a commercial coin dip to remove haze from Proofs. But unless you really, really, know what you are doing, don't use it on copper. That said, not all Proofs develop the haze.
Okay, thanks. Here is a typical proof set that I would want to clean: http://coins.ha.com/c/view-image-on...nment+Proof+Set....+(Total:+5+coins)+Image+#1
First of all you have to understand something, not every coin is a good candidate for cleaning/conservation efforts. The second thing is that haze is one of the early degrees of toning, and once it has progressed to a certain point it is no longer called haze, but toning. And once that happens the only thing that will remove it is a commercial coin dip. The coins in that set, I would just leave alone.
