Generate a new CSV file (must import CSV into Lead Liaison) with two columns, Email and "Is Valid" (or something similar).Reduce the CSV to only invalid emails, removing the good emails.Import the CSV, map the Email field to the Lead Liaison Email field, and the "Is Invalid" field to the "Do Not Email" field in Lead Liaison. Note, when you import, you have to import into a List. If you have a general List with all contacts you can simply re-import into the same List without creating a new List; otherwise, you'll need to create a new List and import into it. If you want to delete bad records after your import is done then setup a process to delete all prospects with the Do Not Email field equal to true. Deleting a Prospect also removes them from any Lists they are part of. This step is optional though. You can keep the contacts with bad emails in the system if you like. Keeping them in the system will prevent emailing the same bad emails in the future.
- Do a simple export of only the email, name, and company. Email is the minimum requirement. Exporting more than this will just increase time to export/process in Lead Liaison as all other fields are superfluous for the purpose of validating email addresses.
- Take the excel sheet and validate the emails using your 3rd party of choice. Any of the following services should work well for you: