"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. 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.