If you folks search over in the gun smithing and handloading forums, you'll find a lot of cleaning chemistry and methods detailed. The main take-away is that modern cleaning chemicals introduced over the last ten to fifteen years have made brushing pretty completely unnecessary. The main problem is the average user either uses obsolete chemistry or just doesn't give the chemicals time to work. If you don't let them work five to twenty minutes, you are patching out unexpended chemical agent.
When you are cleaning multiple guns, the longer sit time is easy to achieve. You just go from one gun to the next, and pretty soon it's time to go back to the first gun.
20 minutes is about the longest most common bore cleaning chemicals keep working to any significant degree, but I've had Gunzilla keep penetrating and pulling deep carbon out a pitted bore (whose pits were glazed over with solid carbon) for several weeks. Same with Mobile 1 motor oil's detergent agents. On another track, Wipe Out's product called No Lead is the best lead remover, IMHO, and it has to sit 60 minutes. But the most common modern chemicals I use, like Boretech products or the KG products are normally fully expended within 20 minutes. They are most active during the first 5 minutes, so the 5 to 20 minute time frame is marks when it the time to patch them out or refresh the application if needed.
I've tried several systems, but here's what I do most of the time now: I carry a couple of pump sprayers to the range with me; one with Boretech Eliminator and the other with Gunzilla. For rifles, after they've cooled enough to keep my hand on the barrel, I pump a couple of squirts of Eliminator into the chamber with the muzzle is down. This is to let the product run down and wet the whole bore. I plug the chamber and bore and pack up and head for home. By the time I get home, unless it's a stubborn and very heavy fouling bore, the bore fouling is all dissolved or loose. I run a wet patch followed by a dry patch. Done.
Eliminator has excellent corrosion inhibitors and can be allowed to dry out in a bore. It's water-based and almost odorless, so my wife doesn't complain about the "smells" creeping up from the basement. But if I don't know when I'll shoot the gun again, I usually follow up with LPS-2 or other corrosion inhibiting oil.
For handguns, I carry a pump sprayer of Gunzilla and spray the bore and, after a heavy shooting session, will field strip and hit the rest of the mechanism with it while still at the range. I then put the gun in a plastic bag and head home. By the time I get there, all the fresh carbon comes off easily with a small rag or an old toothbrush wet with the same Gunzilla. Ed's Red or Mobile 1 also works for the home cleaning if you prefer them. The thing I like about Gunzilla is you can just wipe off the excess and it leaves a lubricating film that doesn't attract dust.
If the pistol bore has metal fouling, I clean the Gunzilla out with a short spray of carburetor cleaner or Bore Scrubber before applying a loose wet patch of KG-12 for copper or of No Lead for lead fouling. KG-12 sits 20 minutes. No Lead sits 60 minutes. A dry patch followed by a wet patch of Boretech Eliminator and 5 more minutes before a final dry patch. Done.
The reason for using Boretech Eliminator at the end is to get carbon that was under the metal fouling and to test for remaining copper. KG-12 does not turn blue or green as it eats copper. It just gets a sort of light orange-brown. What makes it great is it is both fast and has a huge capacity for dissolving copper. Eliminator does not have that sheer capacity, but it is also very fast and it does turn blue in the presence of copper, so it's a good indicator of the presence of copper. It's so fast, it will turn a patch light blue from attacking a brass jag just in the time it takes to push a patch through the bore. For that reason, Boretech sells special alloy jags (their Proof Positive line) that aren't attacked by their copper solvent products. I have those for rifle, but just use old Hoppe's plastic jags for handguns.
To clear up one point of confusion: Scotch-Brite and its imitators have abrasives intentionally bonded to their Nylon substrate fibers. That's why you can buy them in
different grades from rough to polish. Plain Nylon will not abrade like Scotch-Brite does. Indeed, it's a popular material for plastic bearing bushings, such as are used on a number of rotary tumblers you can buy.