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How to scrub your email list for better open rates and ROI

Corina Leslie
Corina Leslie
Reading time:12 m

Scrubbing an email list is a recognized marketing-hygiene method that helps you get the most from your email database. Simply put, it’s removing outdated information and false contacts.

But the bigger the database, the better, right? Wrong. The degradation rate of email list databases is about 22,5% a year. It is a natural process as people change jobs and abandon their emails. And there’s no point in keeping these orphaned addresses on your list since they will never bring any return.

For the marketer, an email list is a daily go-to tool; you need it to be sharp and run smoothly for maximum ROI. Scrubbing emails reduces your costs and ensures your emails actually reach recipient inboxes, improving the click-through rate. All these factors affect your business’s top line.

When do you need to scrub your email list?

Aside from regular maintenance scrubbing, these red flags point to a need to clean up your email list as soon as possible:

  1. You see a decrease in deliverability. If you’re experiencing a decline in the percentage of emails successfully delivered to recipients, it’s likely because you have inactive or invalid addresses on your list.
  2. You get low engagement. If fewer people are opening and clicking through your emails, it could be because they’re no longer interested in receiving them. 
  3. You notice an increase in bounces. A high bounce rate indicates that you have invalid or inactive addresses on your list. But be cautious as not all bounces are similar. There are hard and soft bounces — the former need to be removed at once, while the latter can be worked with and reengaged. A soft bounce is due to a lack of space in the recipient’s inbox and, thus, temporary; hard bounces are permanent, as in the case of a false email, deleted email, or address typo. A healthy bounce level is considered 2%.
  4. You’ve got too many unsubscribes. This is a sign that your content is no longer relevant to them. It is OK and happens in many industries. Just remove these from your list while working on growing your list simultaneously.  
  5. You’ve received spam complaints. There are several reasons why people may send these. It’s essential to identify and address the issue to stop your emails from going to spam.
  6. Their information has changed. If you notice changes in any of your subscribers’ information, contact them and update your records. And if you can’t get in touch with them, it’s best to remove them from your list entirely to be sure that everyone on your list is who they say they are.
  7. You used to buy an email list. This is particularly true if you don’t know how the previous owner collected the addresses or whether they obtained permission from the subscribers. As a result, you could risk violating spam laws or having your messages marked as spam.
  8. You are changing technology. If you are moving to a new CRM (customer relationship manager) or ESP (email service provider), or modifying your CDP (customer data platform), clean up your email list to ensure that you don’t jeopardize your updated platforms by carrying over bad data from the old ones.
  9. You are running a reengagement campaign. To get better results, remove spam traps and risky addresses from your list before sending emotional “We miss you” messages.

Now, how do you scrub your list? What’s the best way to do it, and what tools will you need? Let’s look at that next.

How to clean your email list in 7 steps

If this is your first time cleansing an email database, you may want to run it from a “disposable” mailbox first.

Set up a new account on Mailchimp, SendGrid, or similar platform for testing purposes only. Run all your experiments here before moving good addresses to the network or service you usually employ. This way, you may check off all the bouncing and invalid addresses and test out different creatives without burning your primary server reputation.

The email-scrubbing process is straightforward and doesn’t require specific skills or creativity. All you need is consistency and diligence.

You will need several tools to scrub your email list, especially if you are working with larger databases. We’ll look at the tools and links below. 

Note that to get through the scrubbing process, you must have your email list in a file format, preferably CSV. If your email is in the mailing system, find out how to export the database first and save it on your computer. 

Follow these steps to clean up your email list: 

1. Validate the emails

Separate the valid emails from invalid (i.e., typos, nonexistent) or inactive email addresses. To do this, run your database through one of the email validators listed below. These tools are not free, but their pricing is reasonable, and most offer automated duplicate removal and bounce management. 

2. Remove the duplicates

Usually, the mailing systems would track the duplicate contacts and merge them. If this is not the case, export all your lists and combine them into one. Download it as a CSV file, open it with Microsoft Excel, and remove the duplicates by clicking Data > Remove Duplicates.

3. Remove unsubscribed contacts

This step is straightforward. Most ESPs will allow you to segment out all unsubscribed contacts into a group, and then you can delete or archive them. You can see an example of how it looks below.

Remove Unsubscribed Contacts Step One

Step 1 of removing unsubscribed contacts

Remove Unsubscribed Contacts Step 2

Step 2 of removing unsubscribed contacts

4. Remove contacts who have marked your emails as spam

To find these, check your email service provider’s reports. Spam complaints can also be a reason behind soft-bouncing emails. Once you identify people who have marked your emails as spam, remove them from your list. You can do it manually or using an automated tool.

Note: In most cases, spam issues go far beyond someone marking your email as spam and include proper mailbox configuration, your sender reputation, and other factors. To help you cope with these, we take care of all the necessary settings as a part of our cold email service.

5. Reengage the less active subscribers

As you scrub your list, separate quality users into 3 categories depending on their actions. For instance, Gold (active, opened, clicked), Silver (active, opened), and Bronze (active). Move the Gold addresses to your “clean” list. Keep pursuing the less engaged subscribers through 4 to 5 more emails with different creatives. If you cannot engage them, determine whether you still need them on your list. 

6. Remove the inactive subscribers

Double-check the inactive subscribers’ histories and make the decision. If they ever opened or clicked your emails in the past, you may keep them. If they have made a purchase but have yet to opt-in for the email marketing, send them an opt-in request. But the subscribed non-openers have to go. Below is the example how it looks.

Remove Inactive Subscribers Illustration Example

Removing inactive subscribers example

7. Segment your list to send more targeted emails

To give you an idea, Mailchimp allows you to break down your audience based on their activity, purchases, money spent, and so on. You can cross-reference this information with the address, personal details, and sign-up source. This data combined gives you great insights for crafting personalized emails. 

Go slowly, send segmented emails, and carefully follow the ESP’s limitations. Be patient and measure your results; you will end up with clearly defined segments of users who are all engaged, interested, and responsive. 

Note: If you’ve done all of the above and your engagement is still below average, get in touch with our email deliverability experts and they’ll help you spot the issues and fix them.

Best tools to use for email scrubbing

Choosing an email list scrubbing system is essential for email deliverability and sales performance. Though there are many third-party services in the market for this, try reaching out to your ESP first and asking if they have any validation and verification tools (for example, SendPulse has a built-in validator). These are ideal first choices because they will never trigger your ESP’s spam filters or safety protocols.

Otherwise, you can use other market leaders for different aspects of email scrubbing.

1. Email list validation tools

Validation is a process that helps to ensure that the email addresses on your list are legitimate and deliverable. There are a few different tools you can use for this.

  • Bounceless uses various methods to verify emails, including checking the DNS records, checking for typos, and more. It can also integrate with a dozen other tools, including Mailchimp, SendGrid, and Constant Contact, to name a few. It even offers to verify your first 100 emails for free.
  • Snov.io Email Verifier lets you swiftly check individual email addresses either directly through the app or with the email address checker extension. If you have larger batches of emails, the bulk email verifier is designed to enhance your email campaign outcomes by verifying entire lists. Additionally, Snov.io’s email verifier API allows for direct integration into your platform, facilitating real-time email validation during registration or lead form sign-ups.
  • NeverBounce offers a variety of features, including the ability to upload lists of up to 100,000 contacts at once, real-time verification, and more. They boast the fastest turnaround, promising to clean 10,000 emails in 3 minutes. As a trial, they offer a free database analysis to help you determine if your list needs to be cleaned at all.
  • Clearout is a bulk email verifier that helps businesses ensure their emails reach the right inbox. The service's advanced validation checks ensure 98%+ accuracy, and it seamlessly integrates with all popular platforms. Clearout offers flexible pricing plans, and businesses can test and verify 5 emails for free. Upon signing up, businesses will also get 100 more validations for free.
  • ZeroBounce is an industry leader with a user-friendly interface and some guarantees. They promise 96% accuracy rates on AOL, Yahoo, and Microsoft 365 email accounts and 98% (or more) accuracy rates on everything else. Your first 5 emails are free to validate.

For even more information about email bouncing, what it means, and how to deal with it, watch this episode of the Belkins Growth Podcast with ZeroBounce’s COO Brian Minick.

2. Email list segmentation

Segmentation is dividing your list into smaller groups based on criteria such as location, interests, purchase history, and more. It helps you send more targeted and relevant emails to each group. Here are some tools you can use for this:

  • Mailchimp offers email list segmentation, among other features. It can help you segment based on opens, clicks, recent purchases, location, etc.
  • ActiveCampaign lets you create segments based on multiple conditions. These can be your usual demographics, “Action” conditions, or “Contains” conditions; you can also intertwine them by grouping your segments.
  • Moosend is straightforward and simple. It lets you create segments by cross-referencing different actions and conditions and immediately work with them; make a targeted campaign, toss, copy, or export.

3. Email bounce management 

Some operators offer distinct bounce-management features, which will make sense if you work with large databases and can’t afford to toss hundreds or thousands of bounced emails. This tool will analyze the bounces for you and give a detailed report to define your further actions. 

  • GlockApps Bounce Manager reports on the bounces and splits them into hard, soft, blocked, unsubscribed, or complaint emails. It also allows you to filter bounced emails by sending domain.

How often should you scrub your email list? 

The correct answer is regularly. In a perfect world, you’ll continually keep your email list in top shape, but this is a hard status to maintain. The optimal frequency for thorough cleanups is once a quarter, but you can perform them more often if you frequently send emails to large lists.

In addition, if you use an email marketing platform, you can set up automated email scrubbing to ensure your list remains up to date.

How to reduce email database degradation

Once you’ve scrubbed your email list, keep it as clean as possible. There are several ways to ensure that the contacts on your list remain positively engaged with what you’re sending them. 

Build a quality list from the start

Quality list building means adding contacts who have opted in to receive your emails and are interested in what you say. Add opt-in forms to your website or blog, or use lead-generation tools to grow your list. With a double opt-in system, people must confirm their email addresses before being added to your list. It helps to ensure that people are really up for getting your updates. 

Use automation

You can set sequence triggers based on where your subscribers come from or what their actions are. This will significantly increase the chances people will open your emails.

For example, if your reader has clicked on the link to a particular product in your letter but has yet to purchase it, your next step might be to send them a discount offer, encouraging at least one more interaction. And the next day, you may remind them that top items sell out quickly. This trick works perfectly in B2B and in B2C, and here's the example how the Museum of Modern Arts (MoMA) store did it in the sequence.

Automation Sequence Example by Mo Ma

The chances are high that subscribers will open these, as they’re logical, meaningful messages from the brand — and each opening will keep those contacts active, adding to the email database’s score.

Final thoughts

By following our tips, you can ensure that you only spend your money, time, and effort on reaching interested prospects. Tend carefully to your address “garden” by removing the weeds and nurturing subscribers with tailored communication. You will reap the rewards of outstanding ROI and CTRs for all your hard work.

And if you are still experiencing any issues, take a look at our blog post on how to improve your email deliverability.

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Corina Leslie
Corina Leslie
PR Manager at ZeroBounce.net