Sometimes Terry, flea market vendors have the same chips in their display cases that are exposed to sunlight week after week, month after month, and the effects are similar to what Charles K has illustrated. If the same side of the chip is continuously exposed to uv rays ... the other side is protected and does not show the effects of UV light. I recall seeing paper money mounted in frames on the walls of local businesses; lunch counters, barbershops, taverns, coffee shops, etc. that were displayed as their first dollar taken in upon opening. Same thing ... discoloration from UV exposure. Not only from sunlight, but from flourescent lighting as well. Tiny Treasures sells chip frames with UV protected glass for this very reason.