i am building a rock wall for a 135 i am putting together. my question is fairly simple i suppose. what is the best method to clean the old base rock before i start building and foaming? it has been sitting for some time now and want to be sure it will be safe to put in the tank. i have thought about bleach, acid, just spraying them down with water.... what do you guys think would be the best way? is any of that even necessary?