It used to be that I could use Excel to load up a text file and modify it, then save the file as .tsv (tab separated file). There wouldn't be any comma/quotes added to the output file.
However, I just found out that the new version of Excel (probably 2007 and up) has this annoying feature where it would add comma to the file. So, when Excel saves the file it modifies any column with quotes. It puts quotes around the whole column, and then double any quotes within the content of the column, i.e., " -> "".
After much digging, I find the best way is to just copy out the content and paste into a text editor, such notepad++. So here are the concrete steps:
To save Excel file into tab separated file (without quotes added):
1. In Excel, select all (Ctrl-A)
2. Copy (Ctrl-C)
3. Open Notepad++, paste (Ctrl-V)
4. Save (Ctrl-S) and done
I don't know why Microsoft would make such a annoying change to Excel, but the above should be the best way to save or export the file without those annlying added quotes.
By the way, the other way people mentioned on the web would be to run a script in Excel, but that seems like overkill.