Take some baking soda in a small container. Use a toothbrush to apply the baking soda to the gold. Scrub the dirt out of the gold. When working on a larger piece of gold, rinse the toothbrush with water from time to time to clean it. Use the toothbrush to apply more baking soda to the gold. Continue to scrub the gold until it is clean.
Hold the gold under running water to rinse it thoroughly.
Pour a few drops of dishwashing soap in a small bowl. Add club soda to the soap. Place the gold in a strainer. Lower the strainer into the soap mixture. Allow the gold to soak in the mixture for around 5 minutes. Use a toothbrush to clean and polish the gold. If the gold features an intricate design, carefully clean the dirt embedded in the crevices of the design. Rinse the gold under running water.
Use a soft, dry cloth to buff the gold. Rub the gold with the cloth until it shines.