In case the mold remediation has spread to the pages, you will have extra work to handle. If the pages of the book are dry you can easily brush off the visible mold and then dampen a soft cloth with hydrogen peroxide to treat the pages. But do not forget to place a waxed paper between the pages to protect them. However, if the pages are wet, care has to be taken so as not to destroy them. Before trying to brush off the mold from a damp book make sure that the book is completely dry first. This will prevent smearing and grinding of the pages.