The conventional wisdom is that the inlay of a chip left in the sun will discolor and come to look much like this chip.

When I got this chip it was in this conditon. It had obviously been in a key chain/moneyclip as the other side had a lot of glue residue on it.
Rather than simply throw it in the garbage I decided to put it in the sun and see how long it took for it to discolor like the other side.
This is how it looks after a week in the Las Vegas Sun.
There is no noticable difference although I should have scanned it before I put it out on the porch rail.
I'll try to remember to update this a week from now.