Polishing a brass plaque can be done with a few simple steps:

1. Gather your supplies: You will need a soft cloth, brass cleaner or polish, and a small bowl of warm water.
2. Clean the plaque: Wipe the plaque with a soft, dry cloth to remove any loose dirt or dust. Then, dip the cloth into the warm water and wring it out. Gently wipe the plaque again to remove any remaining dirt or debris.
3. Apply the brass cleaner: Apply a small amount of brass cleaner or polish to a clean, soft cloth. Rub the cloth onto the brass plaque in a circular motion, applying gentle pressure. Make sure to cover the entire surface of the plaque.
4. Let it sit: Let the brass cleaner sit on the plaque for a few minutes to allow it to penetrate the tarnish and grime.
5. Buff the plaque: Using a fresh, clean cloth, buff the brass plaque in a circular motion until it shines. If there are any stubborn spots, you may need to apply a bit more pressure.

With these simple steps, your brass plaque should be looking shiny and new in no time!