Books left in a dampened environment for a time can take on an unpleasant musty odor. Method one provides a way to remove the odor using baking soda. Method two uses newspaper to absorb musty odors.
Remove the book from the damp environment. See how to repair a wet book if your book is actually wet.
Allow it to dry out thoroughly. It helps if you leave it opened in a warm room, such as a lounge room or sun room.
Baking Soda Method
Sprinkle a little baking soda between the pages of the book once dried. If it is a really large book, sprinkle every few pages. However, the odor will remain if you are not diligent in adding the baking soda, so it pays to be patient and take a bit of time to do this.
Leave the book sitting open for a few days.
Remove the baking soda. You can either brush the soda out with the palm of your hand or using a soft makeup brush if the book is really precious and delicate. Avoid shaking the book to remove the baking soda unless the spine is very strong and the book is in otherwise strong and excellent condition.
Repeat if the odor persists. Alternatively, make a decision about the worth of a very badly damaged book and decide whether it is better off recycling and buying a new copy. Sometimes the damp can have so thoroughly damaged the binding and paper of a book that it cannot be saved.
Place sheets of newspaper between some of the pages of the book.
Crumple up newspapers. Stuff the crumpled papers into a box or suitcase.
Squeeze the musty book into the crumpled papers. Shut the lid of the container and leave for a week or so. The newspaper will absorb the musty odor. Dispose of the newspaper in the recycling bin when used.
You cannot rush this; prepare a cup of tea and sit somewhere comfortable and resolve yourself to having to spend some time to achieve this result. If you have a lot of books in this condition, try to rope in the whole family to create a "production line" of deodorizing!
These are time-consuming solutions. Prevention is always better than cure; always store books in a dry environment.