I imported a text file into SQL Server 2005 today and ended up with squares at the end of the last column. Turns out the text file, despite being tab delimited, had a tab prior to CR/LF at the end of each row. I was confused at first as to how to get rid of the squares, but then I figured it out.
SELECT ASCII(RIGHT(column,1)) FROM table --gives 9, which is TAB in the ASCII table
UPDATE table SET column = REPLACE(column, CHAR(9), '') --replaces tabs with nothing