Baking potatoes turn into custom stamps for fabric paint; to obtain the best results, use shirts made of washable cotton.
Flowers
Each part of a decoration can be made with a separate potato stamp. For this design, we cut a blossom with a flower cookie cutter, leaves with an aspic cutter (normally used for shaping jellied garnishes), and a stem with a knife.
Stars
A large, simple shape like this star is easiest for younger kids.
Letters
Use letter cookie cutters to spell out names. Place cutter on potato half so letter is backward; cut out. Turn stamp over, and dip into paint. The same method works for numbers.
Polka Dots
A fingerling potato makes great dots -- just cut off the tip.