Just tried Thorro Clean bore cleaning system on a ( clean bore ) . Been using kG carbon remover & Butch's bore shine , so I know my barrel is clean ,right? My test used the plastic jig & nylon brush so as no brass or bronze contamination to soil my test. Uh, following the instructions it looked like black mud came out, also lots of blue . I did a second cleaning to see if the solution did the same thing . Nothing , patches came out clean. So I think this stuff does what it says. I sometimes spend an hour cleaning my barrel, this stuff cut it down to 5 mins. Barrel looks like a mirror. We have a match this weekend , hope this improves my score. Not going to scrape my other cleaning agents just yet. But will give Thorro Clean the 2 thumbs up