I clean mine with rubbing alcohol after shooting...I then run 1-2 dry patches through and then lube well with WD-40...Next I run a dry patch through and then use a good gun oil...When I am ready to hunt, I run 1-2 patches down and load up, so I still have a coating of oil in the barrel...

I do this with both my inline and my 2 flinters, have been doing this way for 30 years or so with no problem...Some think black powder absorbs oil, lube, etc and won't ignite, I've never seen this problem...