Patina refers to the natural weathering of copper due to airborne sulfur compounds, which gradually change copper’s surface color. The resulting color, called a patina, depends on location and climate. Salt, moisture, sunlight, ultraviolet rays, and pollution can affect the final color. In general, copper progresses from a natural salmon color to a series of russet browns and grays, and finally to a blue-green or gray-green patina. To maintain the shiny look, apply a car wax immediately after purchasing the post cap, and reapply every 3 to 6 months. To encourage a natural patina, remove the lacquer with mineral spirits and grade 0000 steel wool.