Mix cornstarch, salt and water together.
In a small pot, cook mixture over medium heat until it forms a ball of dough. Move dough to your work area and allow to cool slightly. As soon as it can be comfortably handled, knead it a few times to check for consistency. It should be soft and pliable but not overly sticky. If it is too sticky, add a little more cornstarch.
Roll dough to ¼ inch thickness.
Cut out ornaments using cookie cutters. If desired, use a large stamp to create a design over the top. Tip: When it’s time to gather your leftover dough and re-roll to make more ornaments, wet your hands slightly before you knead. It helps the dough integrate better.
Using your straw, create a hole for the ribbon that will hang the ornament.
Place ornaments in the oven and bake at 250F for two to three hours, or until completely dry. Flip occasionally – exactly how long is needed will depend on how thick your ornaments are.
Wipe off any excess cornstarch that may prevent paint from adhering, then decorate with paints and/or glitter if desired.
Optional: If you want your ornaments to last for years and years, seal them with three to four thin coats of non-toxic acrylic varnish after the decorative paint has fully dried. Make sure to coat the entire surface to prevent moisture from getting in.