Can't remember the seller on ebay a few weeks back but I was interested in some of his silver coins until I checked his feedback including his feedback as a buyer and noted he bought a silver cleaning kit a few weeks ago....
Welcome to the Forum Punchy. As you can tell no one on this site likes to clean coins and thinks that it is a bad idea. If you think you have junk coins that you would like to pratice on (which I think you should not do) then can you post some pictures so that we can better advise you on? I would hate for you to clean a coin that could be worth some money.
This time I agree with you'all, This time I agree with you'all - in that junk silver good be a rare doubled die and this collector will not know it yet and could ruin it. So leave it along until you gain more knowledge - that silver ain't eating anything so what have you got to loose you don't have to feed it! Now this new collector that we say "welcome" to will want to know how will he be able to tell if he has a rare die variety. The answer just stick around and look, read, ask, and as time goes on you will learn.