How to turn "don't show again" boxes again?

I was mass buying flair for some cards, some of them were ♦♦♦♦ so there was a pop up that warned me I was spending rare cards. It started getting annoying, so I clicked "don't show again," but after I was done, I realized I might want that to show again when trading becomes available. I can't find out where to uncheck the don't show again boxes for anything except in-battle warnings