This question has options. How would someone go about accomplishing this goal?
D.I.Y clay with cornstarch and baking soda.

pick from the following. (a). Add one cup of cornstarch to 1.5 cups of baking power. Add one cup of water to make a slurry and look till it is the right consistency. Cool and use to mold or sculpt.. (b). Add one cup of cornstarch to 1.5 cups of baking soda. Add one cup of water to make a slurry and cook till it is the right consistency. Cool and use to mold or sculpt..
(b).