I have a table of 4 columns of text data. There are some duplicate values in these columns.

List1 List2 List3 List4
a a f m
b c d n
c e g o
i d m c

I want to be able to identify and delete the duplicates so that I have a table of 4 columns, with unique/discreet values, so that the result would look as follows:

List1 List2 List3 List 4
a e f m
b d g n
c o
i

Is there a way to do this without a macro?
Any help would be much appreciated. Thanks