How do i get the smell of mildew out of some cookbooks i bought.

https://www.youtube.com/watch?v=GEAdzLouUvI

vanilla extract can get a multitude of odors out of anything including fish smells in a cooler! Pour 1-2 drops on a cotton ball or a paper towel ball, put the books into a container or large bag and close - it may take a few hrs or could take a few days depending on how bad the odor is. The vanilla smell will go away in a few hours - don't let the vanilla touch the books it will stain them

Place in a bag with a bunch of charcoal and set out in the sun!🌞

The smell of mildew is something that is almost never removable. You could try putting the book in the sun, standing book up and fluffing pages. They spray with Lysol.

Try sprinkling baking soda on the pages and let it set in a closed bag or container. Another idea is to try cat litter powder

Sun and fresh air may help, but the vanilla idea sounds good.

Open them up and place them in the bright sun. Turn the pages every few house . If all fails, sprinkle them with baking soda, then close them up in a plastic bag. Leave them closed for a day or so. Then open the bag, and "dust" the books to get all of the baking soda off. The baking soda should absorb the odors.