2x2 Cardboard Flips Advice

Look for ones made with Mylar (AKA boPET, AKA biaxially-oriented polyethylene terephthalate). You could also go one step further and go with air-tites.

Good luck.

Products like 2x2s aren't exactly regulated to the point they have to say what type of plastic they contain.

Even if they say what type of plastic they use, it's just their word.

Imagine you are an unscrupulous merchant trying to sell millions of 2x2s you imported from China. You have heard that the collecting community didn't like PVC, for some silly reason. What would you say about the 2x2s you are trying to sell?

Just back from Hobby Lobby. I bought a pack of 35 for $3.99 by Whitman. Nowhere on the package says "mylar". However, the coin pages by Cowens/Whitman says mylars sold separately.

Those ones you get from Hobby Lobby are definitely mylar. they may not be the cheapest but they are safe. It is pvc as in the pages you need to stay clear of.