TARNISHING:

All precious metals (brass, copper, gold plated) will eventually tarnish over time. To help prevent tarnishing store your piece in a clean, dry anti-tarnish bag similar to the one provided. Do not wear your jewelry in the shower, hot tub, or swimming pool. Humidity can speed up the oxidation process that causes tarnish.  Minimize jewelry contact to chemicals such as lotions, hairspray, and perfume.  

GOLD-FILL: 

It's an actual layer of gold-pressure bonded to another metal. Gold filled is not to be confused with gold plating as filled literally has 100% more gold than gold plating. Gold filled is much more valuable and tarnish resistant. It does not flake off, rub off or turn colors.The thick outer layer of gold makes it highly durable and safe for people with allergies or sensitive skin