To clean brass naturally, wash it with a solution of water and gentle liquid dish detergent, peel off any lacquer, polish the surface with a paste of table salt and lemon juice, and then rinse. Applying olive oil to cushion the object from dirt completes this process.
Start by heating water to a lukewarm state and pouring the water into a kitchen sink. Add gentle liquid dish detergent to the water, and mix to form a uniform solution. For a lacquered brass, dampen a cotton rag with the solution, and use the rag to wipe off dirt from the brass surface. Mix a few teaspoons of baking soda and washing soda in water, immerse the brass object in the mixture, and boil for a few minutes. Remove the brass from the water, allow it to cool, and then peel off the lacquer.
For a nonlacquered brass, immerse the object in the soapy solution, and allow it to soak for a couple of minutes before washing with a cotton rag. Be sure to use some pressure to remove stubborn dirt, and clean the nooks and cracks with a bristled toothbrush.
To polish the brass, make a paste of table salt and lemon juice, dub the paste onto a soft cotton cloth, and use the cloth to polish the brass surface before rinsing off the paste. Blot the surface dry with a clean cotton cloth, and apply a thin layer of olive oil over the surface using a soft cotton cloth.