Silver can turn a bit darker with the time, you can clean this easily with a silver polish that you can buy at any grocery store or with a bit of dish soap and a old toothbrush to slowly brush and clean the metal.
You can also leave the jewellery for 15min in hot water in whish you have added some lemon juice and bicarbonate.
The silver I use is eco-silver and is never plated because I love my pieces to be pure and to keep their appearance and to slightly oxidate with the time for more character. I even suggest to wear the silver pieces as much as you can as it get darker when left alone for too long.
The gold pieces are plated on recycled silver, we call it gold vermeil.
The company use 18 carat gold/3 micron gold plating.
To keep your gold pieces in good conditions, Do not swim, bath or shower with your jewelry and avoid exposure to heat and moisture and perfume when possible.
When removing your jewellery it is safer to put it back in the little pouch or boxe that is provided when purchasing a Nouare jewelry piece.