Try this with a few pieces to see if it is suitable for the whole serving. In a pan big enough to hold the amount of silver you wish to clean, pour in enough warm but not hot water to cover thoroughly, Add about a cup of baking soda that's been pre-disolved with about 1/2 cup of salt. Into this add several strips (about 1 inch wide and the width of the roll) of aluminum (ya'll call it aluminium, no?) foil.
The process will start very soon. It's not violent but you will notice a slight smell of rotten eggs. The tarnish will be removed from the silver and deposited on the foil. Leave it in for a good hour or so.
When complete, rinse the silver in hot water and dry and buff thoroughly. If there are any tough spots remaining, rub it gently with any cheap, white toothpaste using your bare hands since the body oils help in the process... rinse, dry and store, wrapped in a soft cloth, preferably cotton.....
Best of luck!