The Compare & Remove tool lets you quickly remove one list from another in a few clicks. Please use caution as once removals cannot be reversed, though you may be able to use the Merge Lists tool to add addresses back, if necessary.
The Compare & Remove tool is found on the Lists Tab, under the List Tools menu.
Select the List that will be altered. This is the list, from which addresses will be removed.
Select the List containing the emails that are to be removed from the Target List.