This advice comes from Ruth Walker (www.feltmaker.com)
Make sure your wool is clean before you store it. After you clean it, put it in a brown paper bag that is double folded and stapled at the top. Wool moths will chew through plastic bags to get to the wool but they cannot chew through the paper.
Attach a small amount of the wool to the outside of the bag so you know what's in there and don't have to open it to look.
This means that I have a weekend long project ahead of me. In fact it may take several weekends to accomplish this. Since I use many colors and types of wool in each project, I'll save out one small basket and watch it carefully for signs of moths.
I have found some sites that tell what to do to get rid of the moths once they find your wool. Here are some of those suggestions:
1. Moth larvae do not like light. Take wool sweaters out of closets and drawers every couple of weeks (life cycle of moth is 21 days) and shake them out or hang them out in the sun. This might work for our craft wool, too. If the sun decides to stay out for awhile, I'll try putting my wool in a mesh bag and hanging it on my clothesline. I'll shake it up a bit for good measure, too.
2. Wash in hot water (above 120 degrees F). This is supposed to kill the moth eggs and larvae
3. Freezing is also supposed to kill the moths.
4. There are various chemical concoctions available but I cannot speak to how safe they are. I haven't found anything yet that I would trust to be non-toxic.
If anyone else has other suggestions, please post them here! It is so discouraging to open a bin of wool and find that it's being eaten away.