Susan is a collector and not a chemist. She gives good advice to coin collectors but uses imprecise terminology. The Wikipedia entry that David linked to is technically correct; it is not the PVC that can cause damage to metals but the oily plasticizers that make them fiexible.

The warning about the handling of acetone that can dissolve the plasticizer is also pretty extreme. Acetone is used in some paints and laquers and for them to dry, the solvent has to evaporate. It's not partiularly toxic; it will dry your skin like alcohol if you apply a lot of it and let it evaporate. The environmentalists banded together to greatly limits its use in industry but in my opinion, it's another application of extreme measures to a situation that is theoretically a problem but statistically of negligible importance.