This thing works like a charm, it's called the sonic scrubber. I had gotten on this road that ended up being a road under construction. First I had to wait forever, then I had to follow a truck and a follow me truck, then I ended up following a road grader that was grading gravel where no road existed anymore, then came the water truck from the other direction. What a mess I had gotten into. Got a lot of gray gunk under the left fender in what I call the catacomb area. The sonic scrubber made the task of getting things clean a piece of cake.
Get one.