So far, all my Shooting with Cap and Ball Revolvers has been with home-made Grease-Wafers between Powder and Ball, and, clean up has been very easy, with plain Dishwashing Soap in Hot Water...using a few daubs of twisted Paper Towel and a Dowel Rod for shoving them through the Bore.
Got a Bore Brush recently for the Cylinder Bores, so, twisting that in there, under Water, also.
All in all, fast-enough and easy...
If immersing the semi-demounted Frame in an Ultrasonic Vat...I'd imagine one would best remove the Wooden Stocks.
Since I do not immerse the whole Frame, I have been leaving the Stocks on.