Ice cubes to clean black tank

There are several issues wrong with the various videos on this. first is the use of smearing peanut butter on the sides of the tank. nothing is going to rinse/bump/etc. that off. often the ice cubes are dumped into a tank half full of water, all they do is bob along merrily in the tank. a minimal amount of water with ice cubes sliding back and forth has to knock off some debris however minimal that is. can't hurt, may help, why worry about it?
bumpy