Expert: Dan Moore - 8/3/2009

Question
Hi Dan,

I have been collecting silver proof sets since 1992 and noticed that however I store them a coin or two might develop a haze on it.  I store them around 68 degrees all year round and are kept in Intercept Shield boxes with silica gel packets for moisture, and still a few coins hazed.  I googled the cause of this and found two answers, one said that it's the plastic cases from the mint and another said it was due to how the mint washed them.  Is there any truth to this and is there anything I can do to prevent this from happening to new sets?  Also, are only proof coins vulnerable to hazing?

Thanks,

Answer
Patrick,

Prettymuch all I can do is confirm your findings -- both the plastic cases and the mint washing can cause this hazing.  If you've ever tried to find a NON-hazy 1974 proof Eisenhower dollar in the GSA "brown box" you will know exactly what I mean.

Pretty much what you are doing is about all you can do -- any more is luck of the draw -- if you get a set that starts hazing, replace it with a new one -- most dealers would do a set-for-set trade with a couple dollars incentive added in.

Proofs are much more susceptible to this because the mirrored finish shows it much more easily, but I have seen it on uncirculated coins too -- even those still in their original bank rolls.

Wish I could offer more help,

Dan