Do not use Silver Dip it cleans by dissolving and removing some of the surface silver. You will soon be down to base metal. Either use the silvercloth as suggested or put a piece of kitchen foil in a bowl, add a couple of handfuls of washing soda, very hot water, and leave the silver to soak for about 5 minutes.
You can put them in a bowl containing aluminium foil and a teaspoonful of bicarb. This will remove the tarnish in an instant and I have never yet found that it removes the plating. Rinse and dry gently. Don't ever rub too hard.
One thing NOT to do is to use a rubber band to hold several of them together. I did that with some cutlery from MiL, and when I went back to it after several months, it had nasty black marks from the sulphur in the rubber. It took ages to gradually get rid of.
I have been given a set of very pretty EPNS cake forks and a server. They are tarnished and I wondered if anyone could tell me the best way to clean them.