How to make your own reusable shopping bag
Decide on your design
Iron the bag
Put the piece of card inside the bag to prevent paint going through to the other side
Paint on your design
Wait for the fabric paint to dry - overnight, or at least a few hours. Depending on your paint instructions
Don't forget to take it shopping with you.
The reusable bags should be washable, although leave it a bit longer to do so just in case. I only did one side of each bag but once the side is dry you could turn over and repeat the pattern on the reverse as well.