As mentioned the uth should be on the outside of the tank therefore cleaning the inside with liquid cleaner and out side where UTH is you just wipe it off.

The easier way to do it is to mount you UTH on a piece of sheet metal that the tank sits on. Then when its clean up time you just left tank up and clean, leaving the heating element stationary. I do this with tubs as well for my quarrantines. Just remember you thermostat probe must always be on the outside of tank on heating element directly so you need to leave space for that.