Over the years we have found the only sure way to protect everything is moth crystals. If we get something questionable we have a few empty containers that we put the stuff in and let it sit for a few weeks with a small pile of crystals in it. The only time we ever have a problem is due to lazyness. Every 6 months to a year depending on how much we open the container we put in a small handful of crystals. Another thing to remember is that just because it is dyed does not mean it is safe. Just a few months ago when cleaning up after the flood we found a container of dyed capes that had not been touched for years. When we opened it almost everything was dust and there were shucks all over the place.
Joe