Pro Shot copper solvent is my copper remover of choice now, a smith friend tested it by sawing a barrel into several sections then plugging and filling them full of various copper removers and letting them sit for 24 hours. Then he sawed the sections in half, copper was gone but the barrel otherwise unharmed with the pro shot

Anyway I do the 1 shot clean for the first 5, then 3 round shot and cleans for the next 5 or 6 or until I don't get any blue, then 5 shot rounds and clean til I don't see any blue.