iritadragon
If you're trying to increase the value of your antique brass tray, you should know that most dealers consider "polishing" old brass one of the most heinous crimes imaginable. The money is in the patina, or the years of wear accumulated. If you were looking upon this as an investment, you have probably decreased the value to almost nil. There are professional restorers out there that could have avoided this.

Caroline H
Polishing brass is fine - it is bronze that should never be polished. There is no way to remove the lacquer without damaging the brass.