There is tinted yellow lacquer for coating brass, but any brand of clear gloss works fine.
Deft clear wood finish gloss in a spray can is a good brand.
Spray an even coat on without getting any drips.
You can use multiple light cots allowing about 30 minutes between coats.
The next coat actually melts into the previous coats.

Thanks, Brickeye. I appreciate your advice (as always -- you've answered a lot of my questions). I've never heard of Deft -- do you know who carries it?

Evil Orange has Deft.