Silver jewellery can change colour over time. This phenomenon is called oxidation (the darkening of the piece). Fortunately, it is only a surface layer and does not affect the quality of the piece, and it can even occur with jewellery that has been sitting in display cases and never worn.

To preserve the shine of your silver jewellery, avoid contact with chemical products such as perfumes, cosmetics, pool chlorine, and cleaning products.

The first step before cleaning the piece is to check whether the silver to be cleaned is protected with a layer of lacquer. If the silver jewellery has a lacquer coating, it can be cleaned using a soft, dry cloth.

1. Cleaning silver with salt
Pour hot water into a bowl — just enough to cover the jewellery you want to clean. Add salt and aluminium foil cut into small strips. Now, submerge the piece in this mixture. Let it sit for 5 minutes. Once you see the silver's shine has returned, you can remove the piece from the solution. Rinse the piece under cold running water to remove the salt, and dry gently using a soft cloth or microfibre towel. The silver jewellery should look as good as new. If you still notice signs of tarnish, repeat the process until it's clean.
Note: If the piece has gemstones, make sure they won't be affected by being submerged in salt water. This solution is gentle on most stones, but if you need to clean fine jewellery with expensive stones, it's best to take it to a professional, as a precaution.

2. Cleaning silver with toothpaste
Simply use toothpaste and a soft, dry cloth, or even an old toothbrush you no longer need. Rub it over the tarnished, dirty silver, and after a few strokes it will shine again. Then just rinse with water and dry to admire its shine once more.
If you'd rather not use any homemade tips to clean silver, you can find various types of silver-cleaning products and metal polishers on the market.