There was a book written about "Soapy" Smith some years ago, with that name in the title, I believe.

He apparently got the name "soapy" from a street-corner scam he would run. As the crowd watched he would fold dollar bills, and larger denominations of paper money, into the paper wrappings of a pile of bar soap. He would then sell the soap for a small sum and people would buy, hoping to get a bar with a big bill attahced. Of course he did some sort of sleight of hand and none of the soap had any money attached.