The following technique assumes you have two files, each of which has one email address per line. It also assumes neither list has any duplicates.
Firstly, take the list of email addresses to be deleted, and append it to the bottom of the list of all email addresses. Now sort the file (via Edit/Sort Lines). You should have one file, with all the emails that need to be deleted having two entries next to each other.
You can find all repeated lines using this regex:
(.*)\n(\1)\n
Open the Find panel, turn on the Regex flag (the .* button), then press Find All: all duplicated lines should now be selected, and you can simply delete them.