Yes – you certainly should clean any areas that you find mold growing in your home. Sadly, books and the like might need to be thrown away. However, walls, ceilings, and furniture can often be saved if you keep washing the area with warm water and soap a few times.
Drying out the mold with a dehumidifier will help eliminate mold growth, but it won’t’ remove it. In fact, after the mold dries, it may release even more mold spores, which will scatter through your home and contaminate your dehumidifier. As such, it is essential only to use a dehumidifier if you intend to clean as well.