If you have email addresses to remove from your Default Test List you can easily remove those addresses from any Campaign under Testing > Send a Test Email.
1. Go Email > Email Campaign
2. Click on the name of any In Progress Email Campaign to open it.
3. Select the Testing tab of the Campaign.
4. Select Send a Test Email.
5. Click the blue x by email email address that you would like removed from the test list.
This removes the address from the list, no other action is needed.