I have found that regular ordinary toothpaste is a great way to clean silverplate. I remember reading this one day in a book and gave it a try. What you do is get a very soft cloth such as felt and apply a nickle size amounts to the silver(all over the item) then let it dry for about 2 hours. Then take another clean  soft piece of felt and wet one corner squeeze out excess water and apply wet felt all over the item(this distributes  the dried toothpaste) then take another piece of dry felt and rub(buff) all over the item to be cleaned. You will find that the toothpaste lifts off alot of the old tarnish and the silverplate item becomes bright and shinny!! I clean all of my silver this way.