What could be causing my Modern Commemoratives to be turning a golden yellow color. I took them out of my safe the other day to show them to a friend and discovered the toning. They are still in the original government packaging. I checked a few of my other coins and it is not happening to them ie: Silver Eagle Proofs. It only seems to be happening to the commemoratives dated before 1990.

Is this toning hurting the coins value?

CC

That's your problem right there, the US government doesn't know how to package coins. Honestly there is little you can do to actually STOP the process, but you can slow it down with humidity control, and air purification. Otherwise they will tone over year to whatever color they please, but on the upside, reds purples and blues come after the golden stage!

As noted air, gases, moisture have been able to attack your coins. Fortunately if in a safe, probably safe from criminals. Unfortunately what you have in the safe when you close the door stays there. IF high humidity, some type of gases, etc. they are still there. The original packaging is just not air tight in those instances. A safe is good and also bad. As to the value. Some people like the toning and others will not buy them with toning. There are even toned coin forums.

Anytime the toning adds eye appeal the value increases. Sometimes like coins will tone differently, or not at all, while under the same condition as the coins that tone. Sometimes it has nothing to do with the environment they are stored in, but more to do with the metal lamination's molecules and how they are mixed before used as a coin.

Some people love toned coins more than those with a luster. They buy only toned coins. Me I like coins without a tone but a luster to them. I have seen toned coins that are beautiful so don't get me wrong I would buy one if I liked it. So I wouldn't worry about the tone on your coins................Doug