How to Patina Brass

Clean the brass thoroughly. Use acetone and a soft-bristled brush, scrubbing gently to remove any impurities from the surface of the piece. Never use steel wool or a metal-bristled brush, as these materials can scratch the surface. Rinse away the acetone under running water and allow the piece to dry thoroughly.

Select an aging solution. There are many chemicals that will age brass, each with its own unique attributes. A combination of vinegar and salt will create a traditional, chestnut-brown patina. A combination of nitric acid and copper sulfate will produce a much more pronounced, dark finish. Household bleach will remove some of the harshness and shine from the finish while keeping the brassy color. Ammonia vapor will create an extremely dark finish.

Place your brass item inside of a lidded container that's large enough to allow space on all sides. Pour the aging solution into the container until the brass is completely submerged. If you're using ammonia, simply saturate a cotton ball for small brass items, or a rag for large jobs, and place it in the container beside the brass.

Seal the container and allow the solution to sit for 3 or 4 minutes. Open the container and check the patina level of the brass. If you would like a darker finish, allow the brass to continue to sit covered, checking every 3 minutes until you achieve your desired effect.

Remove your item from the solution, and rinse it thoroughly under running water. Allow the brass to dry thoroughly before use.