Two years ago, about a year after the purchase of our boat I decided to finally tackle our seriously gross cabin lights. This is a medium tarnished one, light fixtures near water sources (galley, head) were worse.
We polished a few by hand with Bright Boy and with Nevr-Dull both of which worked but were very labor intensive. I came across a tip online to soak your brass overnight in Kool Aid. I bought Kool Aid packets - the kind you still have to add sugar to. Then I added water but not sugar.
I soaked the first fixture for about 1.5 hours and it was a lot better. However, I soaked two more overnight (because I was running out of time) and the results were amazing.
The Kool Aid cut the elbow grease down to about 10% of what it took without.
Anything with citric acid as the first ingredient probably has the same effect.
Brass is a high maintenance item if you want it to look good. It has been 2 years since the Kool Aid project and the fixtures are dull again. No pitting, no grossness, just dull. My thought is that the longest I can get away with doing them is every 2-3 years. If I do them in the next year, it will be a quick and easy job - not painful at anchor. If we wait longer it starts getting back to the big job it was the first time.
That, right there, is the balance we are trying to find. Do enough maintenance, often enough, that painful jobs are avoided when possible but not trying to stay ahead of the curve any more than that.
Warning: The Kool Aid *will* dye your hands. Mine were green although they are only lightly green after a shower ;)