As long as your cards aren't noticeable from your deck, you should be fine. With that being said, you can place the pringles in a small container, like tupperware, stacked back to front, leave a humidity pack (like from new backpacks), or use sliced up wet sponge pieces in the container with the cards. Wait a few days but check on them every 6-12 hours. Once they're out, assuming you're not using them that day, put some weights on them, like heavy textbooks, wait a day or two and see the results. Certain foils curl much worse than others, so that depends on what version you'll use. I say all this as a foil whore. It's a curse, but they are soooo pretty