If you want your pomanders to last, store them in a paper bag and cover them with ground spices completely. Shake them every day to make sure they are covered with spices. Cloves are natural preservatives as well as cinnamon. The spices will draw out the juices and the pomanders will shrink in size. You will know that they are dried inside when they make a hollow sound. The process of drying takes about 3 weeks.