Using the funnel, fill the bottle two-thirds full with warm water and a few drops of food coloring. Add the dishwashing detergent and baking soda to the liquid in the bottle and give it a gentle stir.

Baking soda; Food coloring; Contact lens solution *Vinegar (Optional ingredient that can be used for cleanup.) Elmer's Glue. $13.52. ... (Image credit: Live Science) Step 2: Add baking soda.