James, I've tried the up and down method with the brush chucked into an electric drill,ust using the drill as a convenient, heavy handle. That seemed to work pretty well. I also haven't noticed anyone mention copper vs. steel. The brushes I used to get from the ammo suppliers were copper. The ones I got from the piano suppliers were steel. The steel ones lasted longer. I haven't done this for a long time and I've forgotten the sizes I used. Bob Anderson Tucson, AZ
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