Smelly Jelly Air Fresheners are made from amazing little polymer crystals that expand and hold up to 400 times their weight in water. We treat the crystals with color and the finest fragrance oils to create our air fresheners. To extend the life of your Smelly Jelly add water as it evaporates. Air fresheners make nice gifts for people that are in Hospitals, Nursing Homes, or for use in offices, where you are not able to burn candles. Available in a wide variety of fragrances.