sorry, I don't know C#...
There should be no need to clean / replace the thorn character, just configure it as a delimiter for the source.
FF Source doesn't offer thorn as a possible alternate to comma (in the header row delimiter drop down), so I use Derived Column to replace the thorn character with | in this way:
REPLACE([creative_idþgroup_idþdateþimpressionsþclicksþpublisher_costþavg_posþavg_cpcþconversion_type_idþconversionsþrevenueþlast_modified],"þ","|")
...and it works in al 43 flat file imports except for this one. How would you do this?
--Quote me