Winter storage tips, how to keep the critters out?

Looking for any tips to keeping the critters out during the winter months. I've been using a tarp over the mast and hull and moth balls to keep the critters out. Seemed to work a couple of years ago, but last year got the critters back. Thinking of storing the mast separately and using some lumber as a spine for the tarp and try to seal it up a bit better. Anyone have some good tips that work?  Heard of using dryer sheets, irish spring soap...?

David, FS3289