I too have had this problem... My solution was to purchase a couple of mattress/box spring zip up covers. They are like big plastic bags for mattresses you can zip up. Sold for allergy prone people, they work great in keeping out ferrets. Both my mattress and box spring have been safe and sound since my purchase 2 years ago. Take Care, Moscha (with Skippy, BoBo, and Nosette happily dooking) [Posted in FML issue 5020]