Proper care must be taken when polishing sterling silver so as not to damage it. Silver is renowned for its beauty, but it is also a relatively soft and sensitive metal. It can easily be scratched or dented. The malleability of silver is one of the reasons for its popularity for decoration and jewelry, though it is also one of the reasons why one must be careful while polishing it.
How to polish sterling silver will depend on a number of factors, such as the type of silver, its size, thickness, and the amount of tarnish it has. Certain items such as cutlery will require very delicate polish to avoid visible hairlines and permanent damage, and should be dried with a cloth that will not leave visible hairlines, such as a microfiber cloth. Paper towels, for example, can leave hairline scratches on sterling if used to dry it. However, paper towels can be used to dry the sterling if it is gently tapped on it, rather than being rubbed forcefully. It is advisable to buy a polish with a reputation for quality, such as Connoisseurs. A polish can come in the form of a cloth that is chemically treated as well as a paste that is mixed with water. Generally, pastes are more abrasive and harsher, though this may be what is needed on certain pieces. Pastes may come with a sponge to polish the silver. On jewelry, a soft polishing cloth will usually suffice.
On items with very heavy tarnish that cannot easily be removed with milder abrasives, particularly larger pieces, stronger abrasives can be used, though some would disagree on this point. From my experience, pieces that have been left for years to collect tarnish can be stubbornly resistant to milder abrasives. A harsh abrasive, such as baking soda mixed with a little bit of water to be rubbed forcefully into the heavily tarnished part of the silver, should only be used as a last resort, and should not be used with collectibles of very high value. However, harsh abrasives can be effective at removing tarnish and creating a very lustrous appearance on large pieces. The disadvantage with harsh abrasives is that they leave hairlines, but it is worth noting that hairlines can be polished away over time with milder abrasives. A harsh abrasive can thus be an effective short-term measure to remove a stubborn layer of tarnish.
Another method to removing tarnish, though considered extreme by some, is to place the sterling into a bowl or pot of very hot water — up to boiling — mixed with baking soda (one cup per gallon of water) and a sheet of aluminum at the bottom. In this process the tarnished silver, known as silver sulfide, returns to silver due to a chemical reaction when it comes into contact with the aluminum. The advantage to this method is that the silver is preserved rather than lost from polishing the outer layer of tarnish.
It should be noted that, as a general rule, silver coins should not be cleaned. Once silver coins are cleaned they are considered “damaged” by many collectors. These methods of cleaning apply to sterling silver jewelry, flatware and hollowware, and decorative items.
Sterling silver should generally be polished every six to 12 months, regardless of use, to preserve its beauty and prevent the buildup of tarnish. To prevent the onset of tarnish, there are bags available online for safely storing sterling silver.