A guy I know that shoots a lot of black powder in Cowboy Action shoots says Ballistol does the best job of cutting the black powder fouling. Other gun cleaning products not so good. I always cleaned my black powder guns with hot soapy water, hot water rinse, and a generous amount of WD-40 in the bore to displace any water that gets in the crevices. I store my rifles butt down, and put a patch between the hammer and nipple to soak up anything that collects in the barrel/breech area. Or I snap a few caps if I'm going to use the gun right away.