The air around us contains small amounts of sulphur in the form of hydrogen sulphide. It is this sulphide which reacts with the surface layer of silver to form silver sulphide (tarnish).
How to Remove
Use of many commercial cleaners and all abrasive cleanser/polishes is discouraged as they will remove eccessive silver as well as the tarnish from the surface. Gemstone damage may also result.
So, the idea is to remove the tarnish rather than silver, while being kind to the gemstone! A simple and easy way is with the LotusMoon Polishing Cloth.
But many of LotusMoon's more ornate settings make for hard-to-clean places (see this pendant design for example). Also most silver chains. A neat way to clean these (and also plain items) is with natural baking soda.
This is easy to do in your kitchen as follows,
Note: Do not use this method on gemstone jewellery containing porous cabochon stones like turquoise, coral and lapis lazuli. Especially with turquoise, damage to the gemstone can result. For these items just use warm water only and a soft cloth.
DO ensure you rinse well to remove all excess baking soda. Then gently dry and buff with a soft clean cloth or a LotusMoon polishing cloth.