maroon scotch brite will also help, barring a complete lead-lap, as Scota4570 noted, which is best.
Taylor and I salvaged a .40 longrifle he's made long ago, in which the owner ALWAYS cleaned with boiling hot water.
That rifle was always cleaned before a drink of water, beer or anything else - 1st thing's first, with Peter. After swabbing
the barrel out, it dried immediately and before he could shove a patch down it, RUST. Very fine, but it is accumulate. Taylor
could probably give you the age of that rifle- early 80's or late 70's maybe?
After Pete passed on, Taylor got that rifle back and the bore was finely pitted, end to end.
Using an adjustable lead lap, we salvaged the barrel. In the mid 70's I used a lead lap to not only polish, but lap in a .002" to .003"
choke. You could feel it when loading or cleaning. Shot amazingly well with 1970's GOEX and bullets lubed with Beeswax/Vaseline, 60:40.