Actually hot soapy water will remove most of the powder fowling in the barrel. You can tell this because all of a sudden the patches come out clean in the water bath. To remove the lead, you need to get a bore brush in there.

I use solvent with the brush. That is all a matter of choice. I also run solvent patches through the barrel after brushing because I could care less if the barrel is seasoned.

If you have any doubts about the inside of the bore, drop a bore light down there. It is amazing what some of the old rifle bores look like. I have one old rifle that still looks almost like new. I would have throught with all the brushing and scrubbing after shooting, it would have shown a lot more wear. At least there was no rust. Bore lights I feel are a great investment....