Neutralizing/ removing the mothball/naphthalene smell from textbooks

I was recently given some excellent (and very expensive) academic textbooks. Unfortunately they must have been immersed in mothballs for a long time. When I take them out of the box, the smell of naphthalene actually gives me a headache within minutes. I have tried airing them, covering them in sodium bicarbonate, but nothing has worked. Any ideas please?


