Marie protected her credit cards by finding her son some of his own:
Around when he turned one-year-old, our son started to love to play with our wallets, especially the credit/bank cards and licenses. We didn’t want to risk it (we all know how fast a toddler can lose something!) so we started giving him his own ‘credit cards.’ We keep the cardboard (and occasionally, plastic) mock cards that come with some junk mail/credit card offers. He has a little gift card tin he keeps his cards in which he loves opening and closing, taking them out and putting them back in again. He’s only allowed to play with his cards so now ours are safe! He also has an old photo license of mine that he loves to play with too. Once we can find a child’s wallet that is washable and easy for him to open, we’ll be putting his cards, some family pictures, and his own ‘license’ (easy to make with a small photo, paper, and a sheet of laminate) in it so he can have his own wallet.
Related: Hotel card keys as play credit cards