The bag, of ice cubes, down the toilet, with maybe three-five gallons, of water, in the tank and Calgon and laundry soap does well.
Cleaning the sensors may require more water and ice?
I don't know what seals there are down there and Drano is strong stuff.
If you have a big mound of grease well maybe.
This is one reason, we take the time to filly tanks, black and gray tanks to capacity. Withe flush system connected let the black tang rip and let clean water flush for five minutes. close valve and put five gallons or so back in black tank. Turn selector to gray and let her rip and flush and let clean water flush for five minutes or so per mfg instruction.
Many folks develop black tank accumulations, that just dump the black tank and just go.
:)