I rarely clean the ones I have as I like the natural toning. However I have cleaned some in the past. This what I have and do. At the local coin store for $4 I have a 5oz jar of "e z est"
coin cleaner. Generally you would just dip a oin but NOT in this case. Be at the kitchen sink to rince off. With a q-tip get a drop of the cleaner and start in the middle of the silver and work your way to the brass outside ring with a little preasure. DO NOT get this on the brass as it will discolor the brass toning and will look pretty bad. Rince off with water when done and repeat for the other side. Dry off with a cotton cloth.
Dennis