Currently we are sorting these lists by hand and this should be something
that MS Excel could do... How can we acomplish this?

We have two text columns containing similar data. We want to identify which
values exist in one column but not the other.

Currently we sort each column in ascending order. Then manual check the
value in column 1 against the value in column 2. If column 1 is bigger than
2 we insert a blank cell in column 1. If column 2 is bigger than column 1 we
insert a blank cell in column 2.

Once we are complete, we can see what values are in each column because
there is a value in column 1 and column 2. We delete these rows. This leaves
us with only the unique values for each column...

E.g.

We start with these columns:
#1  #2
A1  A3
DA  A2
B4  B3
C1  D9
A2 B5
B9

..after sorting...
#1  #2
A1  A2
A2  A3
B4  B3
B9  B5
C1  B9
DA

...after comparing columns...

#1  #2
A1
A2  A2
   A3
   B3
B4
   B5
B9  B9
C1
DA

...after deleting duplicates...

#1  #2
A1
   A3
   B3
B4
   B5
C1
DA

The final list are all the unique values found in each column.