This is a link
to a blog post about how to remove mold from clothing. You should be able to apply some of this to yarn. I have washed and dried yarn in the skein and it was fine once dry. If there are no actual spores living in your stash then I think airing them out in the sun(you may have to do this several days in a row) will help. I'm basing this off my own experience of living through hurricanes. However, if you really had a problem then you probably should act as though you do have spores. Moisture control
is going be important for you and there are little packets you can buy at hardware stores for this. Get big ziploc bags and store your aired out yarn in these with the moisture control stuff.
I'm sure it will be fine!