Tupperware or old muffin tin (to store the paints)
Ingredients
¼cupcorn starch
⅓cupwater
food coloring (as much as desired)
Instructions
Combine all the ingredients together in a tupperware container, plastic bowl, or old muffin tin.
Use a fork or a whisk to stir the mixture together. I find using a fork or a whisk helps break the corn starch up more than if you only use a spoon.
Notes
I've never had a problem with this staining but you can always do a test patch before letting your child paint your sidewalk. This may stain clothes, so I recommend wearing play clothes for this activity.