It is often very difficult to get factual and specific information out of coin shops, dealers or numismatic suppliers about what their coin storage products are made of.  Usually it is just assumed that these products are coin safe because they are sold by sellers specialising in coin sales and storage is often the boring practical side of the hobby. Even if you, the collector, have an idea about how to recognise damaging pvc and other safe plastics such as polypropylene, PET and PE these materials will often leave you with confusion.

The Purple Penny team recently consulted with one of the biggest coin storage and accessory suppliers in the world asking them specifically about the materials used in their products that they distribute worldwide.  Below is what their US spokesperson replied:

"Dear
The lining of the 2x2” coin holders is made of Polyethylene (PE) – not Polyethylene Terephthalate (PET). PE is vinyl-free and has no chemical softeners or acids.
Generally, products that come into direct contact with coins are non-vinyl. However, the products for 2 x 2 holders that are listed all have vinyl pages.
Sincerely,
Kathy"

Their email tells us that their cardboard 2x2 holders are coin safe.  Put these 2x2's into vinyl coin pages and the holders and their windows are susceptible to chemicals from the coin pages leaching through the holders themselves.  The manufacturer also has a different product in which coins are placed directly into pocketed inserts.  The inserts are coin safe and then slide into album pages which are PVC, which are not coin safe.  Again the coins are susceptible to the chemicals emitted by the PVC coin pages.  Both of these coin storage solutions are unacceptable for the long term safe storage of your coins if you want to keep in premium condition.