List Cleansing Guide for Improved Delivery Rates


Email deliverability is when an email successfully reaches the inbox. This includes tabbed inboxes, such as Google’s Promotions and Social tabs. When an email ends up in a spam folder or is blocked from the inbox altogether, it was not successfully delivered.

There are several factors that influence the likelihood of an email being delivered, and in this article, you’ll learn more about how regular list cleansing is just one of the factors.

Why List Cleansing is Important

Regularly cleaning your contact list is a crucial part of maintaining strong deliverability and a good sender reputation with various inbox providers such as Yahoo and Gmail. There are several benefits to scrubbing your contact list, including the following:

    • Reduce unsubscribe rates
      An unsubscribe indicates a recipient doesn’t want to receive your email. High unsubscribe rates hurt your reputation because it’s a sign of a larger issue with how you collect contacts with permission to email them.
    • Fewer spam complaints
      Some recipients may mark your email as spam if they did not sign up to receive the email or if they don’t remember subscribing. When this happens, inbox providers log the complaint. If there are too many complaints, they’ll start sending more of your emails straight to spam. They’ll do this for everyone you send emails to, not only the people who reported you.
    • Improve Open and Click rates
      It’s simple - when you send emails to subscribers who want to hear from you, they’ll engage with your brand at a higher rate. The higher the engagement, the better your sender's reputation.
    • Decrease bounces
      When an email bounces, it means it did not get to the intended recipient. This can happen because an inbox was full or the email address was invalid. High bounce rates can also indicate there is an issue with the way you are collecting and validating emails.

Inbox providers observe the above information for all email senders and use it to determine if your messages make it to the inbox. As inbox providers get more and more strict, it becomes important to clean your lists so people who want to hear from you continue to receive your emails.

Reduce Hard Bounces

If an email hard bounces it means that someone subscribed with an invalid domain, a misspelled address, or the address doesn’t exist. This is a permanent error and the email is sent back to the sender.

To reduce hard bounces:

    • Do not buy lists.
      You should only send emails to subscribers who have asked to receive them.
    • Do not scrape the web for email addresses.
    • Grow your list organically.
      Add forms to your website that collect email addresses with explicit consent from the subscriber.
    • Enable double opt-in.
      Ensure only confirmed email addresses make it onto your list.
    • Remove invalid emails.
      Be on the lookout for invalid email addresses and remove them from your list. There are free tools that can help you do this such as NeverBounce, ZeroBounce, ListWise, and more.
    • Check for syntax errors
      Make sure all the forms on your website that collect email addresses check for syntax errors before they can be submitted. This will help reduce the collection of invalid emails.

Identify Unengaged Contacts

Emailing subscribers that don’t engage with your brand negatively impacts your overall email performance and sender reputation. Your open-and-click rates go down while your unsubscribes and spam complaints go up. 

To mitigate this, you can:

  1. Identify unengaged contacts.
    Create a segment that captures contacts who have received your emails but not opened or clicked in a certain period of time.
  2. Create a strategy to sunset them.
    Automatically attempt to re-engage them and confirm their interest.
  3. Exclude unengaged contacts.
    Create a list of the contacts that have not re-engaged and make sure they are excluded from future emails.

Suppressed Contacts

When a contact is suppressed, their data is available in AdRoll but emails will not be sent to them. There are several reasons why a contact could be suppressed:

  • Unsubscribed
    You uploaded a list of unsubscribes from a previous ESP or a recipient unsubscribed directly from an email footer.
  • Hard bounced
    A permanent error was identified from a past send attempt.
  • Marked as Spam
    A recipient flagged a previous email as Spam.

Here are a few more related articles for your reference:

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