Cedar Oil [SEP] I have some small pieces of cedar designed to keep moths away but they are getting old and don't have much odor left.  Checking Google is seems if you add this oil it helps.  I dripped some on the balls/blocks and put them in a ziplock bag.  Helped some, I'll see what the moths say.  By the way, don't take a sweater out of moth balls and go through TSA security.  Seems nathalene has explosive properties.  Ask me how I know.