I've always been a fan of a combination of the Lewis/Hoppes Lead Remover screens, Hoppes #9, brass brushes and patches. However, after reading this post (or another), I recently purchased some of the Klean Bore Lead Away cloth. After a day at the range, I used my old cleaning technique until I was sure I have removed all lead from the cylinders and bore of my SS GP100 (patches were coming out clean). I then cut a few patches of the Lead Away (Klean Bore) sheets and pushed them through the bore. I was amazed to see a bunch of tiny flakes of lead on the patch. I also used this material to wipe the front of the cylinder, which I've never been able to completely clean before, and it got rid of all the soot! I should note that you can run new patches through the bore numerous times and the patch will always come out with a black stain. I'm not sure, but this Lead Away cloth seems to be very similar to Flitz polish saturated into a course cloth. If you wipe the outside of the SS gun, the patches rapidly turn black and it appears to polish the surface of the SS.
The package warns that this cloth should not be used on blued surfaces as it can remove the bluing. Its another neat tool for cleaning those tough spots, but you just need to be careful how you use it.