Puncture the top of the teat with a needle or cut a small piece off the top with scissors. Be careful: too large an opening in the teat can cause gagging. Do not allow young animals to chew on the teat. If an animal is chewing, rather than sucking, it has finished feeding and the bottle should be withdrawn. Clean the bottle and rubber teat thoroughly after each use. If dish-washing liquid is used, rinse thoroughly afterwards.