When in doubt, DON'T clean the object is the best rule of thumb. You might remove something that should be there or that the new owner will want to address themselves. You might even want to point out in your text that this is a solid piece, it has a patina of some sort, and (for example) "aside from a light rinse with a clean cloth and warm water the patina on this item has not been disturbed." You are suggesting your own care of this denotes the piece has some value.

If you use a few keywords in your listing title (and this is where the subhead is useful for 50 cents more) "Brass" "Menorah" "Seasonal" "Decorative" "Candleholder" "Vintage" (50's - 60s') along those lines, you can hit enough topics that someone looking for any number of kinds of objects will stumble upon your listing.

It's a good time of year to sell something like that.

SRS