Gold and diamonds.
Mix a small amount of mild dish detergent with warm water and put the jewellery in for a few minutes. Use a baby toothbrush to gently clean the item. Rinse it thoroughly and dry with a cotton cloth.
Sometimes gold can tarnish a bit, especially on the back of earrings, depending on your skin chemistry. To remove that, you can use a polishing kit.
Silver tarnishes when it comes into contact with oxygen and the best way to prevent that, is to wear your silver jewellery often. The oils in your skin will simply help to prevent the tarnish.
When you put your silver away, use an airtight bag. If your silver is tarnished, a jewellery cloth is the best way to clean it.
These beauties from another world loves to be worn, and their glow will only improve when worn regularly. Remember to put them on last, because they are vulnerable to perfume and other cosmetics.
Use only a soft cloth moistened with water and maybe a mild soap when you clean your pearls.