Can't answer the question directly, but tripped over what might be
useful to someone...
Picked up a rock tumbler at a yard sale. Put a bunch of brass
parts (crib pegs) in it, with some clam/oyster shells / sand from
the beach and set it turning.

What came out was NOT polished cribbage pegs, but very nicely
patinated ones. And not just a surface coloring, but a nice,
durable and authentic finish. Previously had tried commercial
preparations, human-generated ammoniated liquids, and several
recipes from books such as Hughes (which has some lovely coloring
options - look for chemsavers on ebay for KMnO4 etc...)

/mark


Robert Salasidis wrote:

I have Richard Hughes Patina book, and many formulae require the
drying to proceed in sawdust over a period of time.

Is there any data / opinions on drying the solid brass objects in a
vacuum chamber (I couls add a little sawdust to support the piece
while in the chamber).