Email list scrubbing, also called list cleaning, is the process of checking email addresses to identify those that are incomplete, incorrectly formatted or will fail with a permanent error and then amending or deleting the list data.
The benefit of scrubbing or cleaning an email list is that it improves the email deliverability ratio and helps you to keep a high sender score. It turn, this allows companies such as Gmail and Outlook etc to assign a better reputation which will allow more of the emails you send to make it to the inbox of your intended recipient.
Sending emails to malformed or non existent email addresses is one of the metrics used when calculating your sender score. A low sender score will mean that less of the emails you send will actually get delivered, therefore it is in your interests to send emails only to good email addresses. The value of data management should not be under estimated.
Another benefit of scrubbing your email list and removing email addresses that would otherwise bounce is it will reduce your costs when sending emails via third party ESP’s such as SendGrid or SES. ESp’s charge according the the volume of emails sent. As an example, a list owner or email marketer removing 10,000 bad email address has the potential to reduce their costs as they are essentially sending 200,000 less emails per month, if mailing daily.