The carboy I have was given to me by a friend. It used to be used for wine making, and I think there was some old residue build-up on the inside. I had tried to clean it with hot water and dish liquid, and letting it soak, but it still wasn't quite clean enough.
I was anxious to try the Carboy Cleaner that arrived last week and that chance came on Saturday afternoon. I was impressed. They recommend using a cordless drill to prevent electric shock. That must be a purely cover-yer-ass statement in case there's spillage onto your drill. I only own a corded drill, so I didn't have that option. But there was absolutely no problem with using it with the Carboy Cleaner.
Unfortunately, I didn't get any decent video of it in action. If you want to see that, you can follow the link above.
All I have to add is that it was able to scrub out that residue with the recommended 5 cups of warm water and one packet of their cleaning solution, using the Carboy Cleaner of course. The water was a light brown when I was done. Just to be safe, did the cleaning process a second time and the water that came out the second time was just a cloudy white as a result of the cleaning solution.
I now have one sparkling clean carboy waiting for me to purchase the remaining equipment and beer ingredients.