I came across this idea on the Family Fun website for bath time wall paint. What a brilliant Idea.
Talk about good clean fun! Your bathtub buddies are sure to appreciate the bright colors of this smearable, sudsing medium. Try dividing the paints into a muffin tin or ice cube tray for an instant palette. But don't try getting your kids out of the bath in a hurry.
½ cup liquid hand soap, clear or white
1 teaspoon cornstarch
Time needed: Under 1 Hour
1. Combine the soap and cornstarch in a small bowl.
2. Divide the mixture into separate containers, then add food coloring one drop at a time.
Caution: Test the paints on a small area of your tub or wall first to make sure they won't leave a stain; darker hues may be more difficult to wash off. Tips: Apply to tub and body with fingers or paintbrushes. Use bathroom cleanser to clean the tub if any color remains. Keep any leftover paints in airtight containers in the refrigerator for up to three days.