Your pillow alone may be home to 40 million bed mites. (To them your head is just one large oily bon-bon). And don't think a clean pillow-case will make a difference... Indeed, if your pillow is six years old--which is apparently about the average age for a pillow--it has been estimated that one-tenth of its weight will be made up of sloughed skin, living mites, dead mites and mite dung.

Autore: Bill Bryson