In my experience, the top card(s) are prone to warping while sitting in the box, so I use the jokers and whatever extra cards they come with to take the hit, swapping colors so it's obvious they don't belong with the deck they are protecting. It seems to help.
Well, they used to include instructions for maintenance to them in older days. I can make a photo for you. My advice.. Keep them in cool dry place, no heat and sunlight accessible. My friends even machine wash them in delicate circle in special net for delicate but it's your choice. I may even test that procedure.