Filter to show only duplicate entries in Excel 2010

Question

I have two files: Old and New. I need to remove any entry that Old contains from New. So I've exported both files to a tab delimited text file, and then merged the two text files so that now I many duplicate entries. My hopes was that I could come up with some formula show only the duplicate values, that way I could just delete them from there. Now how where can I go from the point I am at now?

Example old:

[41] [john] [smith]
[732] [bill] [murry]
[234] [adam] [sandler]
[9029] [tim] [allen]

Example new:

[10422] [bill] [gates]
[11456] [steve] [ballmer]
[732] [bill] [murry]
[24510] [jimmy] [jones]
[41] [john] [smith]
[234] [adam] [sandler]
[78241] [funny] [bunny]
[9029] [tim] [allen]

Example merged:

[10422] [bill] [gates]
[11456] [steve] [ballmer]
[732] [bill] [murry]
[732] [bill] [murry]
[24510] [jimmy] [jones]
[41] [john] [smith]
[41] [john] [smith]
[234] [adam] [sandler]
[234] [adam] [sandler]
[78241] [funny] [bunny]
[9029] [tim] [allen]
[9029] [tim] [allen]

Example of what I want to show:

[732] [bill] [murry]
[732] [bill] [murry]
[41] [john] [smith]
[41] [john] [smith]
[234] [adam] [sandler]
[234] [adam] [sandler]
[9029] [tim] [allen]
[9029] [tim] [allen]

The name of the column I'll be checking/comparing is "voter_id", which is the number field you see in the examples. I'm hoping by just showing these entries only, I'll be able to highlight them all, and delete. Then remove the filter/formula, and be left with something like:

[10422] [bill] [gates]
[11456] [steve] [ballmer]
[24510] [jimmy] [jones]
[78241] [funny] [bunny]

I apologize for making a separate question for this, but I've found a way to ask the same thing a different way, in a manner that would make much more sense for myself. It's essentially the same results, but in two completely different methods.

Answer 1

Try conditional formatting On the home tab - Conditional formatting - highlight cells rules - duplicate values then filter by color and remove duplicates.