I will honestly have to say that I have used unscented bleach for years for rocks and unfamiliar aquarium decorations, it was recomended to me by an old hobbyist who had been doing this for years. Bleach is nothing more than a concentrate of chlorine, or chloride, which dissapates in time, using a chlorine remover, (one that you normally use with water changes) speeds up the process of the removal of the chlorine, or chlorides, I usually rinse repeatedly after a chlorine soak of several days and then add the chlorine remover. I have never had any problems, not that this is a scientific method, but I have to admit that I have had success this way.
Sam