I was moth-free for years in spite of storing raw wool in my house. Then I made the mistake of buying some alpaca and not checking it thoroughly enough. Long before I discovered it had moths, they had escaped from the alpaca and I've not entirely gotten rid of them since.
However, they can be controlled pretty easily. I was going to recommend Ron's Moth FAQ but he beat me to it (and, Ron, I think you've had that up *much* longer than a couple years :) I have found that cloth bags--I use cheap unbleached muslin but old sheets work well if you patch any holes--make a very effective barrier against moths. I keep my fleeces unwashed until I'm ready to use them, and some have been in that condition for over 10 years (waiting for the perfect project, you understand :) Supposedly moths like dirty fleeces better than clean, but I've never had an infestation in a raw fleece. Make a big square bag, with a wide hem at the top to accept a drawstring. I write a large number on both sides of the bag with a wide permanent marker, keyed to samples attached to index cards in my studio. Fleece goes in bag, tie drawstring tightly (I put in a longish cord so I can wind the ends around the 'neck' of the bag), bag goes in closet, and no moths in spite of having them elsewhere in my studio. Back in the studio, I do two things to help prevent moth damage. I rotate things that are on display--skeins, baskets of wool, etc, because moths prefer stuff that's not been disturbed for a long time. And for that stuff which goes into storage, I add lavender in small bags. Neither is a perfect solution, especially for very fine fibers. Moths actually like silk and angora better than any wool, fine wools better than coarse. I have found silk or angora plies 'snipped' by moths while the merino wool ply in the same skein was untouched. So stuff like my angora stash goes into a plastic storage box, and is kept away from sunlight and heating/cooling vents. Whatever container you choose, make sure it doesn't have ventilation holes--cover them with tape if they do, as moths can get through remarkably small holes! And I make sure such containers get a bag of lavender. The lavender by itself probably wouldn't be enough, but together with the other protections it helps, plus has a lovely scent :) When I do find an infestation in something smallish--since they can't get to my fleeces, I always find moths in smaller things--I zap it in the microwave to really kill the bugs. 2-3 minutes on high, with a cup of water to the side to act as a heat sink, doesn't hurt anything (after all, we dye protein fibers in the microwave all the time!), and definitely kills the bugs. Larger amounts of fiber will need longer zaps. I prefer to keep my batches small, for short zaps. And these days if there's any chance a fiber I'm bringing in might harbor moths, I spread it out in direct sunlight on a sheet before I bring it in, leaving it for several hours and moving the fiber so every bit is exposed. Moths really don't like fresh air and sunshine, it seems :) Or I wash it in very hot water (except silk--cooler water for that) if there's any chance it has moths. Very hot means 160 F or higher--not a scientific number, just an effective one. Finally, it helps to do a deep-cleaning of any areas where you put protein fibers or use them or display them or..... Very thorough vacuuming helps get up some of the eggs and larvae, cleans up the scat and old cocoons, and also 'disturbs' the area so the moths are likelier to leave in a huff. I had a bad problem with moths at one point. I do still find evidence of them where I've violated the 'rules' here, but not very often. So I still have them, but I also know what I need to do to keep them under control. I just have to do it :) Holly
