Do the lists contain the same fields (ie first name, last name ..etc)
If you have Excel you can use conditional formatting to highlight the duplicates (Conditional Formatting -> New Rule -> Format only unique or duplicate values -> Select a formatting style). If you format it as a table and then sort by one of the columns then you should see all of the duplicates listed together and you can remove the duplicate rows manually.
Edit: The Robert/Bob thing does cause an issue with this method, but I think it's still a viable option.
Well, I can make them have the same fields, and I'm bright enough to merge exact matches myself, it's the inexact matches that are going to cause me some difficulties.
If you have Excel you can use conditional formatting to highlight the duplicates (Conditional Formatting -> New Rule -> Format only unique or duplicate values -> Select a formatting style). If you format it as a table and then sort by one of the columns then you should see all of the duplicates listed together and you can remove the duplicate rows manually.
Edit: The Robert/Bob thing does cause an issue with this method, but I think it's still a viable option.