Do Ice Cubes in the Black Tank Really Work?

Well as I stated on his site, fitrvjames Round ice is not going to do anything, it needs the corners of a cube to scrape and remove, and his truck bed was a bit small for a bigger tank to really get the slosh going. Good try though, to much time on his hands to do this kind of experiment.
Question for those who was able to check the inside of your tank, How on earth did you do it? Was it clear as James tank? maybe a colon scope???? (colonoscapy)