Chuck,

This is one "variation" that Dick and I disagree on. I contend that these chips started out the same color and have changed because of either dirty hands or some kind of chemical exposure. Perhaps there is a plant in the area that uses a chemical or something that when comes in contact with the chips causes the "dirty" look. This could easily be passed to the chips by residents hands. In my town we can always tell when someone who works at Oxwell pays for something. The money has a unique smell.

I have seen this same type of discoloration on other chips of this type in other places. Also, if you look at the "dirty" ones, you can find many different shades. I tend to think a true variety would be either a or b, not all the shades in between.

Greg