I present another in a series of Using Power Tools In Cleaning Your Gun.
Yes, some of you are either uttering profanities or calling me names. Stop it. You can actually do this without causing damage, wear or display of stupidity.
In this case, I'm speaking of a cordless drill or driver and a chamber brush. Because sometimes you wind up with fouling in the chamber that just does not want to clean out, especially on something old that hasn't been cleaned in a long time.
Start out with the standard: a bronze or nylon brush and your favorite cleaner or solvent, and make sure any loose crud, normal fouling, etc., is cleaned out. Usually scrubbing a brush back & forth a few times, with some twists, will take care of things, then use a jag and patches to clean it out.
If you've got stubborn spots that don't want to clean out, chuck the brush into your drill/driver, soak in solvent, oil or whatever*. Start it turning slowly and work it into the chamber, then back & forth a few times while turning. With a revolver or double-barrel repeat in the other chambers, adding more cleaner as needed. And then let it sit a while; give the stuff time to work. With the brush to work the stuff into the fouling it'll have an easier time breaking it loose. After a while, damp the brush and work it again, then clean with jag & patches and inspect.
That's it. You can repeat if needed. The only advantage this has over doing it by hand is saving wear on your hand & wrist by letting the drill rotate the brush for you. And keep the speed DOWN; you're not trying to drill, just using the tool to rotate the brush for you.
*Most any bore cleaner will work for this. Blue Wonder is really good for this type of cleaning, and a lot of people swear by Kroil; that stuff is the creepiest oil you'll ever see, it can penetrate under most crap and make it easy to remove.
For lead fouling(think firing lots of .38 Special ammo in a .357 Mag chamber) I've hear of people taking apart a copper pot-scrubbing pad(I think it's Chore Boy) and winding a few of the copper strips into the brush to make it more aggressive. If you try that, make damn sure it's a pure copper pad.