Paper money must be soaked in water before wrinkling. After the folds are flat, take out and collect floating water, put it on absorbent paper, let all the famous water on both sides of the coin be absorbed by absorbent paper, air it for a while, air it until it is half dry, then put it in a thick book and change it for a while until it is completely dry, and the coin will be flat. To get rid of the mildew of coins, you can go to a dust net. There is a website on the Internet that specializes in selling moldy coins and stamps. Buy some of their potions, and you can renovate coins.