Does anybody know if you can still buy the cardboard 2x2s that had the square viewing area. I still see a few around with coins in them on ebay and at coin shows. They seem to give you a better view of the coin.
Finally received an answer to my inquiry about the type of clear window in the Lighthouse holders. According to Annalisa Pellegrino - Arslan of Leuchtturm Albenverlag Germany, they are made of - POLYETHYLENE. Now that is good stuff. So polyethylene, Mylar and polypropylene are the ONLY clear windows to trust for short to mid-term storage. Every 10 years or so one might replace, but certainly inspect. I was told that many coins which were put into 2x2's in the 60s and 70s are appearing on the market today. Many have PVC damage, and she warned me, carefully inspect such coins!! Many of the EBAY pics do not show the lurking PVC damage. So fellow CTers beware. I was also advised as desertgem hinted at above, that it is wise to rinse your coins in alcohol or acetone, not water -- (then let air dry) before putting into any kind of a holder. This removes many many contaminates, even those you cannot see.
A great site is this one below, it gives the basic tests which a collector can perform to determine if a plastic or holder is safe or not. http://www.calgarynumismaticsociety.org/caring.html
Google is your friend: https://www.collectons.com/shop/cat...plies-Plastic-Coin-Holders-Lighthouse-Quadrum