First of all, the gold necklaces and pendants of 18K are not easy to fade, but they will turn black after being worn for a long time and look very faded. If it fades, it's fake.

Secondly, 18K gold necklace and pendant should be maintained:

1: I bought a pack of developing powder from a photographic equipment store. When I got home, I put a catty of clear water in a clean glassware, stirred it evenly, soaked the K-gold necklace, took it out in about 5- 10 minutes, rinsed it with clear water, and wiped it with a dry cloth, and it lit up.

2: Take 2g of salt, 7g of baking soda, 8g of bleaching powder and 60ml of clear water, put the K-gold necklace into it after stirring evenly, soak it for about two hours, take it out, rinse it with clear water again, and dry it with a cloth, which will be much brighter.

3. Go to the place of purchase for regular cleaning.