I bought 2 silver cuffs from Souq Al-Mubarakiya the other day, that are old and dirty. I remember once, hearing my friend's mother talk about cleaning old stuff with vinegar, but I'm not sure what to add with it. So I searched the web and it turned out to be baking soda.
So now one of my cuffs is soaking in a half cup of white vinegar mixed with 3 teaspoons (should be 2) of baking soda . we will see the result after 2 - 3 hours