COACH Necklace & Hoop Earrings - Rose Gold / Copper

Barely used and not what kind of metal it is. Both have shiny stones on them. Started to see some oxidation and tarnishing, not sure if there are ways to make them look better. Necklace in slightly better condition since tarnishing is mostly at the back. Necklace has two adjustable lengths. 16” + 2”. One earring tarnished more than the other one.