Air bubbles are an unfortunate thing that occurs when making Rainbow Jello. Try to remove as many of the air bubbles as you can before letting each layer set. There are two main ways to deal with the air bubbles: - Pop the bubbles with a toothpick or spoon. - Pour the liquid though a funnel. Touch the funnel spout to the side of the pan and the liquid will glide into the pan (instead of splashing).