Diy Scratch Off Ideas . A crayon (white if you have one as it wont make the card a different colour, but i only had colour crayons so i used them instead) 4. A new window will open. Growing Play DIY Scratch Off Cards for Kids from growingplay.blogspot.com The detergent prevents the ink from binding together into a. Let the paint dry thoroughly. You don’t need much solution to cover your hearts.