I think what we're seeing is that Chipco uses pigments that migrate very easily off the chip. You will see this if the chip is in contact with anything.

There was discussion of the desirability of using vinyl flips for chips a few months ago. Evidence was presented of a flip that had turned red after storage of a chip (think it was a Chipco... not sure). I have always maintained that there is no practical problem with the use of vinyl flips or pages for storing chips of any kind. Yes, you do get color showing up on the holders under some conditions, but then the color comes off on your hands if you handle them too... it's just not so easy to see [g].