I have a set of KEM 100% plastic playing cards (stargazers model). They're a premium brand and supposed to be long lasting but after opening the box after not using them for some time I discovered that the top card of each deck (10 of clubs and Ace of diamonds) had warped whilst the rest of the deck hadn't.
Manipulating them with my hands, I haven't been able to flatten them out. There is so much spring in them that they are easily identifiable even in the middle of the deck where they will cause the cards above to lift up.
Does anyone know how to flatten or significantly reduce the warping in these type of cards?