On the Navy ships they use something called "bug juice" to clean brass. Essentially it's a concoction like generic Kool Aid. If you are interested I can find out more info.

razorback_m, that would be great--thanks. Does this concoction help keep the brass untarnished longer, do you know? This is a piece that, once you polish it, you don't even want to think about it again for a looooong time...

For added protection:

You can also apply a thin coat of paste wax to outdoor brasses and lemon oil to indoor brasses to help keep them staying bright.
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Rub on olive or mineral oil to keep the metal shiny longer.

Cleaners:
1 t. salt
1 c. white vinegar
1 c. flour
Dissolve salt in vinegar. Stir in flour to form a paste. Apply to brass and let sit 15 minutes; rinse with water and polish with a soft cloth.
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You can clean brass, bronze and copper by rubbing on Worcestershire sauce or ketchup with a damp cloth.

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Navy Brass Polish
Powdered or canned fruit juice.

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To remove tarnish from brass, bronze or copper, dip a lemon slice or rind in a little salt and rub it on the object. Then clean and dry with paper towels.

Grainlady

All those things will remove tarnish from brass and copper....but a commercial cleaner does a much better job....and does it faster.
Try BarKeeper's friend....but that does nothing to keep brass from tarnishing.
Linda C

Thanks so much, everyone--

Does anyone have an opinion about cleaning this, then bringing it to a place to have lacquered? Any value to this?

Yes....they will do a much better job than you can.....and it will stay nice for several years....but eventually will have to have the laquer removed and be redone.
Linda C