I have used simple green for our green ig for the last nine months. It is supposed to be nontoxic, so I just spray it, scrub it and place the ig back in. this is for his climbs, they have outdoor carpet glued on, so they are not so easy to rinse. He seems to do very well.
I've only had my corn since x-mas and have been cleaning up daily when I see something, so I'm not sure I would scrub the whole thing out unless there was a reason, mites, ants or something.