I personally prefer the look of algae on my rocks. I liken sterile rocks to plastic plants. Both look unnatural, but I do clean the front and side viewing panels regularly. What do the rocks in the real world look like? If you must, soaking in bleach and then rinsing very thoroughly is about the best I can do for you. I wouldn't worry to much about chemicals, bleach evaporates very quickly. You just have to make sure you rinse it really good and then let it dry.
-MStatdfield
-MStatdfield
