We have always used the ashes of cigarettes - or, preferrably, cigars - to clean silver.
First ensure that the ashes contain no grit, then add water to make a sloppy paste similar to light cream, dip an old linen rag into it and gently rub over the silver in a circular way. Completely clean before washing in lukewarm water and a bit of soap.
And an antioxidant
If you happen to have cocoa butter soap, use it to wash the silver. Apply liberally to your hands and work into all parts of the silver. If it is ornate, use an old shaving brush to work up lather in the crevices. Rinse well (it will also remove all traces of jeweller's rouge or commercial polish ingredients) and dry with an old flannel (you want all old cloth to minimize lint).
.