You may or may not know that the case itself is made from polypropylene (totally Ph neutral and safe for archival storage) BUT the sleeve on the outside is made of PVC. PVC breaks down chemically over time. This releases a gas which will break down and discolor your games/manuals/sleeve art.
I am not %100 convinced it matters at all since its only the sleeve and the actual game and manual is inside the polypropylene case. You can also re-print you cover art when it discolors (keep copy's of those jpgs you used as http://www.thecoverproject.net my not be around years in the future). Anyways i have decided to buy archival comic or paper back bags. I am going to cut them to size and put the game in that before it goes into the case to be on the safe side.
Just wanted to let you all know (in case you didn't) and get your opinions.
.


