Never never never use a long handled brush in the sink in your wife's clean kitchen to clean a double after an afternoon of shooting black powder shells. Don't ask how I know this!...Geo
You are a brave man. A bit foolish, perhaps, but brave!
FWIW I have always found that the more "field cleaning" one can do before going home the better the chances are that "The Storm and Strife" will be at least tolerant of one's BP shooting proclivities. Just a few alcohol-soaked patches can take out and off most of the smelliest "Schmutz". The alcohol patches can easily be carried in a small "Tucks" jar. (Don't ask me how I know this.) A cleaning jag mounted on the gun's ramrod will be sufficient for this purpose. An swabbing and wipe-down using a couple of oily patches (I prefer Ballistol.) will hold the gun until it can be gotten home for a full cleaning.