Hey all, I have tried a lot of different currency sleeves. In my binders, the thick holders have hard edges and make dents on the binder pages and separators. I don't want the holders to damage other notes when the binder is closed. I picked up these sleeves at a coin shop some time ago. They are thin, clear, flat and soft. I like them a lot because I can fit many more of these in my binder. I found a listing on eBay with similar holders. But I know nothing about their composition and whether they are archival safe. They look like this: http://www.ebay.com/itm/280900785321 The listing says they are made of something called OPP. Does anyone have any more info on them? Thanks!
