Many consumers are wary of buying sterling silver because they believe it will tarnish and be ruined.  This is hardly the case if a few precautions are followed. Being in the silver business for over 25 years, I know that I can take out a piece from inventory from that original year and see a shiny, new pin, or pendant.  The main idea is to keep the piece away from the air and probably the best way to do that is in a zip-loc type of bag, securely closed.

A good silver polishing cloth should be all that is needed for normal maintainance.

If, by chance, some piece of silver jewelry does get oxidized, I suggest that it be cleaned with a mild detergent and baking soda solution.  If the piece is heated in this solution and aluminum foil at the bottom of the pot, the tarnish should come off easily.  Take it out, rinse well, and dry.

A piece that  is so badly oxidized that it has turned very black is also salvagable, but it might mean a trip to a jeweler who can re-buff the piece to a new appearance.  I've had many a good silver buy over the years at yard sales where this black silver was on sale.