No argument about the concerns of certain holders in storage of coins. Only concern is the scientific description of what can happen in such a case.

Mr. Travers is also a coin dealer, a well known one. He is not a chemist as far as I know.

Susan is a conservationist and concerned with the end result of improper storage. She may know the science involved; it's just that I haven't seen any discussion she authored that speaks to what causes the problem... the kind of plastic, or what additives it contains.

"No, no, no" on PVC for coins is a convenient catch phrase. It really doesn't address why.