Way back in the 1970's when I first started BP, I bought two books.
One was Lymans cast bullets handbook.. I still have it
The other was the Black Powder Shooters Bible or handbook.... Misplaced it.
Anyway, the BP shooters book,
Claimed plain hot water was sufficient or add some dish soap.
They also said plain rubbing alcohol.
I have been using plain rubbing alcohol for the last 30 years.
it has worked just fine. look in the barrels of 44's spotless clean (both are 30+ yr old).
After cleaning a patch with a dab of sewing machine oil in the barrel and outside.
None in the chambers, because an empty gun is a useless gun.
I reload paper cartridges immediately after cleaning.
Which begs another question for another topic I will start later.