Google announced that you can now easily add new emails, remove old emails or replace your whole email list quickly in Adwords for Customer Match.
AdWords Customer Match lets you show ads to your customers based on data about those customers that you share with Google. Customer Match is a useful advertising tool for many business goals, from increasing brand awareness to driving performance.
Here is a screen shot from Ginny Marvin with the list management feature:
Here are more detailed instructions from Google on how to use this feature.
Forum discussion at Google+.