X8883

My idiot friend (72) keeps cleaning his coins

My buddy Larry has a huge coin collection and tomorrow hes getting 8 silver dollar Morgan's. Just like all his other coins.....he's going to put silver polish on them and "gently" clean them. These coins are what most consider to be tonned. I keep telling him...pennies pickles dimes quarts and especially those dollars don't ever ever ever need cleaned it ruins the value.

He says cleaning them will guarantee they will sell for thousands on ebay

What can I tell him to convince him that hes wrong?