Ledbetter -- yes, I do use a brush. Without, it really does leave powder (or jacket?) residue behind. (I believe it's powder residue, since jacket fouling usually turns the patch greenish -- though I suppose even Speer, Federal and the like might be using copper plated iron now? Dunno.)
Docj, true, but it does do a very good job considering how fast and well it works. And, I like its low toxicity. I hate to think how many chemicals I've absorbed over the years. I usually wear latex gloves now...