tell me about your toilet!

I have mentioned earlier about rinsing my black tank a few times to get the sensors to indicate "empty" (I use the sensors to tell me that the tank is sparkly clean ;)). In that process I prop the flush disk open and use a nozzle on the end of a garden hose to pressure clean that cavity area you are talking about. I will not use that process after every campin' trip, but will do it enough times to generally make the area appear pretty clean.