There are a LOT of "gun products" out there. I know there are a lot of gun cleaning products, but I still like Hoppe`s, entirely because it smells like it did when I was 18, had just started hunting, and cleaned my 12 gauge or .22. I`ve been seeing a lot about gun scrubber, and wonder, what is the intended use? What guns would you use this one? What condition would they be in to require this stuff? How do you even use it?