Email List Hygiene

What is List Hygiene? Plus, 3 Tips to Clean Your Email List

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The world of email marketing is ever-changing. But even the most well-oiled digital marketing machine won’t lead you to success if your contact list is full of duds. Or worse, if you’ve been blocklisted with mailbox providers (MBPs) and internet service providers (ISPs).

List hygiene is the process of validating your data to ensure you have a clean list of contacts to send campaigns to. 

Aside from avoiding spam complaints, the benefits of maintaining good list hygiene include improved email deliverability, a better sender reputation, and higher revenue from the email channel. Who wouldn’t want that?

What factors influence email list hygiene? 

There are many different factors that contribute to a clean email list. When senders neglect regular list cleanups, issues can arise that make it harder for emails to reach subscribers. This in turn makes it less likely that you’ll receive positive engagement, and can ultimately tank your email program.

These factors include:

Inactive subscribers: Your definition of “inactive” will depend on your business and how often you send emails. But as a best practice, contacts that have not engaged with your emails in 3-6 months should be removed.

There’s a high likelihood that these contacts don’t want to receive your emails and simply haven’t gotten around to unsubscribing. If the contact hasn’t responded in over a year, their email address may even have been recycled into a spam trap. 

If it’s been less than six months, there’s nothing wrong with moving unresponsive contacts into a list for future re-engagement attempts—but these contacts certainly shouldn’t be on your active list for regular mailings.

Keep in mind that Gmail now prompts subscribers to opt out of an email program after 30 days of inactivity, motivating many senders to be even more aggressive about their list suppression strategies. 

Role accounts: A role account is designed to be a specific, task-oriented email address. These accounts do not belong to a singular person—they are almost always monitored by a group with their own individual addresses.

These addresses typically don’t sign up for email lists intentionally and aren’t worth the risk to your sender reputation to continue firing email to these endpoints. Comb through your database for anything starting with elements like abuse@, postmaster@, info@, support@, and so on.

Typo spam traps: A typo’d domain is a domain that is a close approximation of a real mailbox provider (e.g., or These frequently typo’d addresses are often repurposed to catch spammers, and will get you in hot water if you continue mailing to them for an extended period of time. 

Check your mailing list for addresses like these, and compare them to their engagement rates. If you’re sending emails to typo’d addresses (and confirmed you’re receiving absolutely no clicks or opens), you can rest easy knowing they can be safely removed.

Low engagement: If your email subscribers aren’t interacting with your campaigns, it’s best to turn them loose. When it comes to engagement, MBPs and ISPs look for:

  • Recent opt-ins: Have these contacts given their explicit consent to receive your emails recently?
  • Recent purchases (within 120 days): Have they engaged with your brand by making a purchase in the last few months?
  • Recent opens and clicks (within 120 days): Have they recently engaged with your content and/or clicked any links?

If no is the answer, cut ‘em loose.

All of these factors mean that your email campaigns won’t (or can’t) succeed. This dirty data will quickly turn into an ice-cold email list and increase your chances of receiving pesky spam complaints.

So, how do you fix it? Get cleaning!

What is list hygiene?

How to clean your email list in three steps

Savvy email professionals will tell you without hesitation that good email performance is closely tied to good, clean data. Removing the crud that builds up over time in your eligible sending pool will result in a list that will give you a greater return on your email investment.

So, how do you do that? Get to cleaning! That means removing all contacts that are unengaged, fake, incorrect, or otherwise invalid. This can be done by following these email list hygiene tips:

1. Identify inactive contacts

When on a list-cleaning mission, don’t be afraid to take advantage of the myriad of tech tools available to you. Leverage data cleaning software to fix structural issues (typos, inconsistent formatting, syntax errors, etc.), dedupe, and standardize your data. 

Try running your contacts through an email verification software to identify invalid addresses before sending campaigns. You can even take it a step further and filter contacts by undesirable behavior. For example, a filter for low engagement is helpful because spam trap or role account emails aren’t ever going to engage, making them a prime target for removal. 

That being said, you might want to set aside otherwise valid non-responders into a separate group.

2. Try to re-engage

Before rushing to delete your unresponsive contacts, try re-engaging them first. A re-engagement campaign is exactly what it sounds like: it’s an email (or series of emails) sent to a list of subscribers explaining that you’re touching base and would love to hear back if they’d like to remain in your program

To identify prime targets for such a campaign, start by creating a recency segmentation table (like the one shown here) to determine where your value cliff is. For example, you may see a decline in send volume and conversions if you email anyone whose last click was past the six-month mark. 

3. Remove inactive subscribers

Once you’ve identified who doesn’t belong on your list, you can delete the contacts you know for a fact will never engage. And if your last-ditch efforts to re-engage valid, but unresponsive contacts doesn’t work, it’s time to remove them as well. 

It may feel counterintuitive to see perfectly valid email addresses leave your list, but it’s better to have a small group of engaged subscribers than a large group of uninterested ones. Trust us, your sender reputation will thank you.

Tips for maintaining good list hygiene

By now, you know that list hygiene is a must, and will only positively benefit your overall email health. By doing the following, you’ll be able to keep your lists clean and comprised of active contacts only.

Re-engage inactive subscribers

As mentioned above, it’s a good idea to regularly send re-engagement emails to list members you haven’t heard from lately. Remind them why they subscribed in the first place, and try to offer something of value as a way to win their attention (via a strong CTA).

Remove inactive subscribers

Haven’t heard from someone lately, despite your best efforts? Do yourself a favor and remove them from your list. 

Regularly audit your list

Keeping your email contact list clean (read: free of inaccurate, redundant, invalid, and/or fraudulent addresses) requires constant vigilance. In fact, starting at the point of acquisition, there are several safeguards you can implement to verify the addresses you’re adding to your database. 

That said, whether you’re adding addresses through a web form or copying them manually from a sign-up sheet, it’s difficult to be 100 percent sure each address is valid. That’s why regular database audits are a must. Set aside time for routine check-ups weekly or monthly to maintain a healthy, clean email list.

Segment subscribers

Look at inactive subscribers who haven’t yet unsubscribed as an opportunity to learn (and deliver) what your contacts want to hear from you. What do they have in common, besides being inactive? Try creating list segments based on their last click or purchase date. Then, send to each segment separately to gauge performance and identify where the drop-off is. 

Once you identify the drop-off period, you can schedule a re-engagement campaign accordingly. You can also use this approach to send more relevant information to each segment, making it less likely that they’ll ignore your emails (or worse, unsubscribe entirely).

Use double opt-in

Using a double opt-in method will be your best weapon in fighting against a stale email list. By sending a welcome email requiring the recipient to confirm their subscription, you’re verifying the recipient’s identity and getting positive engagement metrics, which MBPs love to see! 

This may seem like a cumbersome step on the surface, but by initiating this one extra touch, you’re putting yourself in the best position for continued engagement.

Use a professional domain email address

If you’ve reached the point in your business where you’re sending regular emails, you most certainly need a custom domain. Setting up a business email through your provider of choice is free. It also looks more professional to both your customers and MBPs.

What’s more, the sooner you get your own domain to send emails from, the sooner your domain will age––another strong factor in your favor when MBPs make delivery decisions.

Final thoughts 

It’s time to take care of your email lists as well as you take care of yourself. Your email lists deserve good hygiene, too! Without it, much—or all—of your mail will not reach its intended recipients.

Remember that your reputation is based on your sending practices, and continuous sending to unengaged recipients or invalid email addresses is a surefire way to tank it.

Looking for more expert tips on email list hygiene best practices? Check out our guide, Clueing in on List Hygiene.