How to Create a Clean Email List & Why it Matters For Ecommerce Brands

When you first start generating a list of email subscribers, adding to that list is your number one priority. But if this remains your only priority, then it can become detrimental to your email marketing success. A large but unengaged subscriber list can harm your deliverability rates, skew your analytics and increase your email service provider (ESP) cost.

Combatting this requires regular list cleaning and maintenance. Without this, you’ll end up paying to contact people who never read your emails.

In this article, we’ll outline both the misconceptions and benefits of email list hygiene, as well as how to begin the cleaning process for yourself.

Misconceptions about email list cleaning

It’s common to be hesitant to clean up an email list. Reducing the size of an email subscriber list feels counterintuitive in the world of ecommerce, where bigger numbers so often equal increased growth, more revenue and better opportunities.

However, in the case of email subscriber lists, bigger isn’t always better. Instead, a top priority for email marketing should be engagement, open rates, click-through rates (CTR) and attributed revenue.

Before diving into the benefits of email list cleaning, let’s first address the common misconceptions around this activity.

Myth 1: A bigger list equals higher chances of conversion

While this may be true initially, maintaining a large list of unengaged subscribers over time can actually harm your email marketing efforts. Low open rates and poor engagement metrics can negatively impact your deliverability and account health, increasing the risk of emails landing in spam—even for your most engaged subscribers.

Myth 2: Suppressed subscribers won’t buy again

This is a common fear, but suppressing unengaged subscribers only stops them from receiving marketing emails. They can still navigate your store, make purchases, and receive transactional messages as usual. In fact, by stopping marketing emails they’re not interested in, you may actually prevent subscriber fatigue and reduce the risk of annoying potential customers—ultimately increasing the likelihood of future purchases.

Many ESPs (like Klaviyo) allow you to retain the historical data you have collected for these suppressed subscribers and use integrations with other platforms to retarget them on other channels.

Myth 3: They might re-engage in the future

While this too may be true of some subscribers, maintaining a bloated list of unengaged users for this small possibility isn’t worth the negative impact on email marketing performance. The costs—both financial and in terms of deliverability—outweigh the potential benefit of keeping these inactive subscribers on your email list. Besides, subscribers can always opt back in to hear from you if they want to.

Benefits of a clean email list

With the misconceptions and myths of cleaning behind us, let’s look at the huge benefits that a clean email list can bring to your email marketing efforts.

A healthier email account

Your email account health is directly tied to engagement rates. By maintaining a clean list of engaged subscribers, you’ll see improved deliverability rates and better overall performance metrics. Email platforms track these engagement metrics closely, and better account health means your messages are more likely to land in a consumer’s primary inbox rather than promotions or spam folders.

Strengthen customer relationships

Continuing to email customers who are no longer engaged with your brand is likely to do more harm than good. This could potentially lead them to mark your email as spam, thus negatively impacting your sender reputation.

By focusing on engaged subscribers, you can personalise content better, ensuring your emails are relevant and valuable.

Improve data & statistics

Whilst your email subscriber list may decrease initially, other statistics will increase. Your open rates, click-through rates, and conversion rates will likely see significant improvements as you’ll be sending emails to an audience that’s genuinely interested in your content. This more engaged audience provides clearer, more accurate data for your marketing strategy – which leads on to the next benefit.

Form a data-driven strategy

With more accurate statistics from a clean email subscriber list, you can trust the data you’re seeing. In turn, this can better inform your email marketing approach and its incorporation into your wider full-funnel marketing strategy.

Reduce costs & improve ROI

Most ESPs charge based on the number of active subscribers in your list. By removing inactive subscribers, you can significantly reduce your associated email marketing costs. This is one example of how optimising your tech stack reduces costs and increases efficiency.

How to create a clean email list

There are a few key tactics for cleaning an email list, but above all, we recommend doing this regularly to safeguard against both a bloated list and bloated costs. Monthly hygiene checks are helpful to maintain a streamlined subscriber list, alongside flows to automate this process.

Here are the key steps to clean your email list effectively:

1. Identify & suppress invalid or outdated email addresses

The first step in maintaining a healthy email list is identifying hard bounce email addresses—those that cannot receive emails due to a permanent issue, such as an invalid domain or a deactivated inbox. Continuing to send emails to these addresses will harm your sender reputation and deliverability, increasing the likelihood of your emails landing in spam.

To prevent this, it’s best to immediately remove hard bounce addresses from your list. Many email marketing platforms, like Klaviyo, and list cleaning services can automatically detect and remove these addresses after the first hard bounce, ensuring your emails only reach active, valid recipients.

2. Identify inactive subscribers

Review your subscriber list and create a segment to identify users who have never opened or clicked your emails. We recommend suppressing these users immediately and retargeting on other channels.

Next, build a segment to identify users who haven’t engaged with your emails over a specific period. This timeframe depends on your send frequency, product type, and typical repurchase cycle. For frequent purchases or consumables (e.g. coffee), three months of inactivity may indicate disengagement. For larger or seasonal purchases (e.g. sofas or Christmas decorations), a longer timeframe is reasonable before considering a subscriber unengaged. Adjust your criteria based on your business model to maintain an engaged and responsive email list.

3. Launch a re-engagement campaign

Before suppressing unengaged subscribers, give them one last chance to stay on your list. Create a re-engagement campaign with compelling content and a clear call-to-action (CTA) asking if they want to continue receiving your emails.

We recommend automating this process using a Sunset flow which will trigger a re-engagement email as soon as a subscriber is identified as unengaged.

Alternatively, for customers who have completed a purchase, you might want to try a specific win-back campaign before suppression. Again, this can be automated in a Winback Flow.

4. Suppress inactive subscribers

For subscribers who don’t engage with your re-engagement or winback campaigns, suppress their accounts, removing them from future email campaigns.

5. Monitor & adjust

Implement automated flows to routinely identify and manage inactive subscribers. This helps maintain list hygiene without requiring manual intervention each time.

Regularly review your email metrics to ensure your list cleaning efforts are improving your overall email marketing performance. Key metrics to monitor include open rates, click-through rates, and spam complaints.

Next steps for a clean email list

Maintaining a clean email list is an ongoing process that requires regular attention, but the benefits far outweigh the effort involved. By following these guidelines and implementing regular list hygiene practices, you’ll see improved engagement rates, better deliverability, and more accurate data to inform your marketing decisions.

Remember that list cleaning isn’t about reducing numbers—it’s about maximising engagement and ROI.

If you are looking for support in this process, get in touch with our email marketing experts.

As a Klaviyo marketing agency, list cleaning is one of the many services we provide, working to ensure that our clients’ accounts remain healthy. We can deliver a one-off project, or provide services as part of a retainer package, depending on your business’ needs.