Natural metals will tarnish based on your skin's chemistry and humidity. To keep your jewelry as shiny as possible, we recommend wearing it except for when you wash your hands or shower. To shine your pieces up, we recommend using a soft polishing cloth -- we like these microfibre polishing squares.DO NOT POLISH OXIDIZED JEWELRY. The black finish on these brass pieces will patina over time and is hastened by moisture. The black finish will gradually antique showing the brass metal beneath but will never become the bright color of brass.