http://www.ehow.com/how_4527277_remove-mothball-odor-clothing.htmlsnip: There are more suggestions ("steps") at the link.
Step1
The old fashioned, and least expensive way to remove mothball odor is to expose the item to as much fresh outdoor air as possible for several days (bring it in at night). It is best to hang the clothes in the sun on and off for at least a week. This seems to work especially well if the clothes are hung dry, before attempting to wash them even once. You may supplement this technique by using a fabric freshener spray on the clothing such as Febreze, while it hangs in the sun. Direct sunlight helps break down the mothball smell, but be careful not to allow too much sunlight on the garment as you don’t want the color or fabric to fade.
Step2
White vinegar works as an odor remover. It works well on mothball odor, mildew smelling towels, body odor, and other offensive odors. Put about 1 cup in the wash cycle at the beginning of the cycle. You may need to run the load more than once. (This method only recommended for machine washable items.)
Step4
Smelleze Mothball Deodorizer is a product that actually removes the smell by attracting it and capturing the molecule from the air. (Most every other odor removal technique is smothering, masking, or covering the odor.) This product is non-toxic, odorless, and all natural. Smelleze is a small pouch that you can hang in a closet or place in a drawer. Just place the mothball affected clothing on hangers, hang the bag right near the clothing, and smells with be absorbed. The pouch can be regenerated by placing in the sun for a few hours. This product costs about $12 per pouch and you can find it on the internet.
(I deleted Step 3. All it said was to not iron the item, because that would just set in the smell, and maybe even make it worse.)