I store my unidentified chips in the popular Cowens 20-slot pages. I put the chips into the slots without using the 2 x 2 flips. These pages are soft (PVC? softeners?). 99.9% of the chips suffer no damage, but I noticed that some of the hot-stamped radial diamond mold chips (red chips mostly) leave a colored image on the plastic pages. Below are pictures of what two chips left on the pages (the chips were removed for the scan). Also pictured below are 3 chips that did damage. (One good thing about this post is that I looked up "Green Light" in the good old The Gaming Table and ID'd those chips!)
............I have never had problems when I put the same chips into 2 x 2 "safety flips" -- those rather stiff plastic flips with the sharp square corners -- and then put the chip-in-safety-flip into the soft 20 slot pages.
Robert