DeFeKt
Aquarium Advice Addict
I'm with tankgirl on this one..I would not worry too much about the sterility of the rocks. I personally take a scrub brush and get the dirt off, possibly douse them with boiling water from a kettle, rinse again and chuck them in the tank.
Some rocks, when exposed to constant hot boiling water could explode.
I to would keep away from the bleach..
If you really want to clean them i suggest normal dishwashing liquid..and a good long hard wash in dechlorinated water..
on a couple of the rocks i got they had little spots of rusty type stuff so i had to drill it off. the bit got really HOT!
Thats why they invented Masonry drill bits, and Hammer drills.