Turpentine and a very tight patch. Just because you have leading problems with the bullets he sold you doesn't mean he did.

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The trick is finding and spending the pesos for real turps. I first heard about turps and lead working in shipyards in Florida back in the 70’s. We would cut up big lead ballast keels with chainsaws and the blade and cut was lubed with turpentine from a squirt bottle. It made a difference for sure as the cut and saw ran smoother. Problem these days is finding good quality distilled turps. Most of the 20-25.00 dollar a gallon stuff doesn’t act or smell like real turps at all. Last two gallons I bought cost me close to $50.00 a gal. I special ordered it and didn’t realize the cost.

If you can't find real turpentine, then you can buy "Lead-away" patches at most large sporting goods stores. Birchwood Casey makes them.
Need to use a good solid cleaning rod, and a jag with the Leadaway patch a tight fit in the bore. If it can be pushed into the bore easily it wont work, so I back the patch with a small rag patch underneath if it needs to be tighter. I want them tight enough that I have to bump the rod to get the patch started down the bore.
I've found these patches will remove the lead in shards shaped like the rifling. One or two patches does it, followed by a 3rd patch that I work up and down the bore to give it a thorough polishing. Even very old bores with ancient lead build up come out much nicer.
I buy Leadaway in cloth sheets and cut my patches to size. They sell it as a sheet, or as patches.

I think bronze wool around a brass or bronze brush would be a better option. Steel wool scares me.

try kroil  wet the bore  let set 15 min  wipe with tight patch repeat as needed kroil lifts the lead   art

Tim I’m assuming based on your endorsement you must be a user of this product. Perhaps you could let us know what the prime ingredients might be perhaps the MSDS info. I for one have found over the years that cleaning agents and compounds rarely contain anything really new but are often just re-formulated, scented, colored and packaged to appeal to end user markets. Hopefully this product is the exception but I for one am a hard, no snake oil, convert. 

Though nobody wants to deal with it but mercury really is the end all answer to removing hard to get at lead deposits. Lab workers work with it all the time so with just some basic care it’s not a problem except for source and price. I cleaned lots of muzzle brakes during my Bullseye days and nothing is easier.

Buy  a bottle of Shiloh Rifle's Bore Cleaner.  It is almost solidly a lead remover.  No soaking but just a tight patch on a jag and it will just release the lead.  Been using it for years and I haven't found anything that is better.