You might use FullForm to inspect the contents of what you Import from Excel. I have seen in the past things coming from Excel are sometimes quoted strings. Mathematica almost always hides the quotes, thinking that it what you would want it to do. So they may already be strings, possibly even nested inside several layers of { }. Perhaps FullForm can most easily tell you.

Bill Simpson gave me a great start on this problem;Bravo! There is one detail that I neglected in re the format of my 'alias' data and that is the data is in text format (imported from Excel) and not in quotes-delimited format. Is there a way to treat that too?