Here's what I use and do:
First, what I use: pipe cleaners, nylon or brass bore brush, small scrubbing brushes or an old toothbrush, patches and jag.
1. Remove cylinder from revolver.
2. Remove nipples from cylinder.
3. In a plastic tub of warm, soapy water (Dawn or Ivory dish soap, or a bar of Ivory soap are preferred) scrub the cylinder with:
A. A few quick plunges of a wet patch on a jag, under water, to blow the excessive carbon out the back via the threaded hole cut for the nipple. This will remove 90 percent of the fouling from the cylinder.
B. .40 caliber brush for the .36 calibers, and .45 caliber brush for the .44s. Twist the brush down into the chamber, so you reach to the bottom. The end of the brush should be seen in the hole where the nipple goes in. A nylon brush works fine for black powder, but use a copper or brass brush if it's all you have. Do this under water, so the carbon can float away.
C. Use a Q-Tip wet with soapy water to reach down into the bottom of the chamber after each chamber gets the brush treatment. Turn the Q-Tip back and forth so it "threads" itself into the threads cut for the nipple. This will get any carbon out of the threads. Again, do this under water so the carbon floats away.
D. Cut a few pipe cleaners into fourths. Then make a short, 90 degree turn on the end of each section of pipe cleaner. Shove this turn into the open nipple. This gives you a handle to hang onto the nipple as you scrub its threads all the way around. Finally, plunge the pipe cleaner in and out of the nipple to clean carbon from inside the vent. Do this under water, if possible.
Pay particular attention with the soapy brush to the threads on the nipple and the shoulder cuts used to thread it in with the wrench. These areas gather a lot of carbon during firing.
E. Place the cylinder and nipples into a mesh, stainless steel collander. The type with the handle works well. Put the drain in the sink, but allow it to drain. Run hot tap water over the cylinder and nipples until they are rinsed of soap.
F. Set your oven to 150 degrees or lower. Open a door a little bit, to let steam escape.
G. Shake excess moisture off the cylinder and nipples, then place them on a towel. With a quick puff of breath, blow out trapped moisture in the nipples from the chamber end of the nipple to the cap end.
H. Run a dry Q-Tip down into each chamber in a circular motion, to get any excess water. When you've done this to all chambers, turn the cylinder over and turn a dry Q-Tip into the threaded hole for the nipple. This will quickly wick away any moisture on the threads.
I. Place the cylinder and nipples in a small baking sheet with a raised edge (so they won't roll off into the oven). The cylinder should be placed on its back, with the chambers up, to discourage any trapped moisture. The nipples will naturally lie on their side with the larger opening facing up, ensuring a good escape of moisture.
J. Place the pan in the oven. Leave it there 15 minutes or so.
K. Remove the pan after all parts are dry. While the cylinder and nipples are still warm, place a suitable lubricant on them (read, non-petroleum). I use olive oil, Crisco, lard (no-salt variety), mutton tallow or any of the vegetable oils such as canola or peanut.
The nipples get a good slathering of any of the above. On the nipple threads, I put a little extra oil or beeswax. This makes them easier to remove after a day of shooting. ALWAYS put some kind of lubricant on the nipple threads or you will likely have a devil of a time getting them out of the cylinder after a long shooting session.
I never use any petroleum greases or oils on my black powder guns, nor should you. Stick with natural greases and oils.
L. Rethread the nipples back into the cylinder, but don't tighten them as hard as you can. A good, firm fit is all that's required.
Steel actually absorbs oil, so don't be concerned about putting too much oil on your cylinder or nipples. In a day or two, it will have soaked into the metal. I leave my assembled gun liberally coated with natural oil for a couple of days, then wipe off the excess.
I've taken pains to be very descriptive in the above. It sounds like a lot of work but actually it takes only a few minutes to properly clean a cylinder and nipples, doing the above.
Every year someone introduces a new Zip-Wham black powder cleaner that is said to be the finest ever made. Every year I try the stuff and find myself going back to plain, ol' soapy water. Save yourself some money. Buy a plastic tub, a bar of Ivory soap and a small colander.
At the range, a small spray bottle of water with a few slices of Ivory soap in it makes a fine field cleaner too. A quick spray on a patch eliminates the waste typical of pouring.