Years ago, some took the barrel off with their T/C Hawkens and cleaned with soap and water...I don't take the barrel off my custom flintlocks, just plug the vent and pour a little rubbing alcohol down the barrel, slosh around and pour back out...

With my Knight, I just clean the barrel with a few alcohol patches or even wipes...Then dry and lube the barrel, pull the breech plug and clean it and the action...