For the record, I'd like to interject here. There are a couple of different ways to sanitize rocks and other objects to make them suitable for your fishes' environment. One is that you
can bleach them - as long as you rinse well.
However, no soap or other cleansers ! These leave toxic residue ! 
As a side note, it is perfectly safe to bleach rocks when cleaning them... just soak them in dechlorinated water for a night or two to remove the chlorine residue before you put them in your tank.
The other method is boiling, which is perfectly OK for things like rock or driftwood, but not recommended for plastic products because of leeching of dangerous chemicals that could inadvertantly end up in your tank.
While we are on the subject, this is also why fish experts advise against putting anything into your tank as a decoration that is not "approved for aquarium use", because of the leeching possibility. I personally talked to some one on a different forum recently that put brand new plastic reptile tunnels in her tank as caves for hiding places, and they looked nice, but after a few months the coating started to chip off from being in the water so long.
The rule of thumb is to remember that your fishes' healthy environment depends on you to be mindful of what you are using in their world and the bottom line should be that if you are unsure of it, then
don't use it.
