Sidewalk Paint 1/4 cup cornstarch 1/4 cup cold water 6 to 8 drops food coloring Mix cornstarch and cold water together in a small plastic bowl. Add food coloring and stir. Repeat this process to create different colors of sidewalk paint. Use sidewalk paint for painting large areas,  such as hopscotch grids, make-believe roads and highways, etc. When done, you can wash it away with the garden hose.