Soap and warm water is a classic cleaning method, and it can breathe new life into your sterling silver.
Combine warm water with a mild ammonia, such as phosphate-free dishwashing soap. Use an old toothbrush and gently brush solution on the silver.
Once done, run the item under warm water before drying it with a clean cloth. It may soon look as good as new.
That's it! That's all you have to do! Of course if you want to go more in depth, or need a deeper cleaning method, check out this post.