In iTunes there is a very useful feature called Show Duplicates.
File » Show Duplicates
As expected by its name, you can use this feature to help weed out duplicates from your iTunes library. However, many people have different versions of songs, remixes, etc., which will show up as duplicates when using this feature.
The solution is to hold down the option key prior to selecting this menu item. When you do, Show Duplicates changes to Show Exact Duplicates. In this mode, iTunes shows only true duplicates, and not remixes or alternate versions.
