Someone posted that he has a sealed tube filled with mineral spirits to submerge his barrel in until he's ready to clean it. That sounds like a pretty good idea if someone doesn't have the time to clean it right away, and I know that he really cares for his BP guns.
Other folks that shoot cowboy action report spraying their revolvers liberally with Ballistol which neutralizes black powder residue and buys them extra time to clean while they need to travel a long way to return home. Sometimes they attend out of state matches that last an entire weekend.
So there's methods that can be used to help postpone cleaning temporarily without damaging a gun.