Question is this. *Some well meaning sort polished and lacquered the
plates for me already, and the knobs will have to be polished before
they are installed as they were lacquered as well but the lacquer wore
off in some places and is crazing in others. *The brass in the rest of
the house (appears to have been originally unlacquered) has a nice brown
patina which SWMBO says she likes better than bright brass, and I tend
to agree with her. *Is there some easy chemical means to acquire such a
patina, or should I just strip everything and polish it bright, install
it, and ignore it for a couple decades?

I built a wine cabinet and ordered a brass grate for it and did not
like the shiny look. So I took a sample and started rooting through
the hoards of chemicals I had laying around for one project or
another, and I also bought a patina chemical from Lee Valley. The
patina chemical, which was not a very large quantity, was expensive.

But then I ran across a bottle of etching solution used for making
your own circuit boards. The chemical is Ferric Chloride, and is
probably available from Radio Shack. If not, check out www.digikey.com.

Using gloves I dipped a rag into the FeCl2 (or is it Fe2Cl?), and
rubbed it on the brass. IMMEDIATELY turned dark. Once I darkened it
completely, I rinsed under water to neutralize the chemical. Then I
took a buffing cloth to give the brass highlights. Worked great.

You can see a b4 and after he

http://www.areddy.net/wood/wine%20cabinet/index.htm

Scroll way to the right in the images and you'll see the virgin brass,
then after the patina.

Or

Befo
http://www.areddy.net/wood/wine%20ca...s/DSC00713.jpg

After:
http://www.areddy.net/wood/wine%20ca...s/DSC00724.jpg