I have tried most chemicals designed for removing gun powder and copper and lead fouling, but have not tried the poor boy thing sounds interesting! but something that i have used and found extremly good is made by Blue Wonder called gun cleaner just fallow the directions, after yur chore is finished and you look down the barrel you notice that not only is the bore nice and shinny like it is brand new but all lead and copper fouling has disappeared, i first used this stuff in my yugo 48a and the bore was just copper fouled out after a few minutes and a little scubbing and letting it rest you should have see all the crap come out i did the prosses twice after the second one i tried the time tested hoppes , and a few dry patches too see how dirty the bore was and that was a waste of time they came out just as clean as they went in.
I then broke out the lead guns only and as the rest of us know that how much a pain it is when we get a real small amount of lead fouling of a bunch well in a barrel that runs real hard lead it lookd a i figuared was clean you should have seen the junk come out of that thing, I've used hoppes most of my life its what grand pa used and dad used and what i will still use but i will be adding Blue Wonder to clean them seriously before a match,oh almost forgot to add ablout my muzzleloaders ( they are all side locked mostly flinters), i lulled the breach plugs and did the same to them and they also are rejuvenated.
Kevin