An oil-rubbed finish is a dark patina on metal. Typically, this finish is dark brown to charcoal gray with some of the bronze, copper or brass showing through at the edges, seams and any curves on the surface. Older bronze, copper and brass items naturally develop this type of patina. The patina can also be created by rubbing darkening formulas on these metals. The chemical reaction created between the formula and the metal will darken the surface of the metal. This is known as an "oil-rubbed" finish.
Wipe all dust or dirt from the unlacquered metal. If any lacquer remains on the surface, use lacquer thinner and buff it away with a rag.
Dispense a quarter-sized amount of darkening solution onto a rag. Darkening solution can be used on brass, copper or bronze. It can be purchased through specialty craft vendors, some home improvement stores and online. Liver of Sulphur will also work, and is available in most art stores.
Rub the solution onto the metal with the rag. The metal will immediately begin to darken. Apply a small amount at a time until the desired finish is acquired.
Getting a satisfactory finish may require practice, and it is best to practice on scrap pieces of metal before you begin your project.