I’m not sure of the character code for a non-printing character. However, if you have say a breaking space - char(10) – you can eliminate it with:
=SUBSTITUTE(A1,CHAR(10)," ")
where A1 contains your string.
You need to do the above type of formula before you run Clean (you may not have to run Clean at all).
To determine the character code of each item in a string (including spaces etc.), download the free CellView add-in from
http://www.cpearson.com/excel/CellView.htm
When you install this add in,
it will add an item to your View menu called "View Cell Contents". Simple select your text, and then click the View Cell Contents button.
HTH
Mike