When we lost our pistols I bought a repo Rogers & Spencer BP revolver. To be honest I had no great love for this substitute firearm and showed it little respect. Usually shot about 100 rds a session using Pyrodex.
The evening finished by pouring a kettle of hot water over the metal parts and a quick spray of wd40. Once in a while the cylinder was removed to check for any build up of crud, never had any excess.
Still a nasty smokey smelly thing.
Good luck, Phil