I had the same question but several years ago at Bellagio and Mirage I was lucky enough to get brand new chips out of the box. They do have solid white inserts but even in airtights they eventually bleed. The bleeding shown in Brian's scan is where the chips were stacked and in contact with each other. In airtites, the chip is not in contact with other chips and the bleeding starts around the edge and in time colors the entire insert.