~~~ rely on Google, though, especially with a defined search.

In a case such as this I would ask; "storage plastic jetons plaques heat breakdown" to start with then "Katie Smith" (posted by, a scientist) with "plastersizers, new car smell, breakdown" for some hits and then go from there. Also, the person in "monaco" posts referring to same words... and maybe some of this would help but, to rely on which dates, I would guess about 2004, onward for starters.

My question has always been... if it's age related, then why are there plaques the same age in their original state of preservation? Thus key in on "storage" for best search results.