All our jewelry is made from brass which is 100% nickel free. All ear wires/posts are either brass or sterling silver. You can find more details and the materials used on each item's description. Brass and silver will oxidize/tarnish with time. The reaction will create a natural patina over the piece. It will just add to the item's personality but if preferred shiny it can be easily removed with a polishing cloth, like the Sunshine.
The best way to care for your jewelry and keep it in it's original condition is to keep it in a clean/dry place. Avoid long term exposure to humidity and crazy chemicals. Try to prevent it from getting in touch with water, remove it before showering or swimming.
With the proper care your piece should last you many years to come!