Email List Cleaning: 6 Tips for Mastering a Clean, Active Email List to Achieve High Deliverability


For 2022, Webbula is launching a series of blog posts about email deliverability topics. We have a variety of esteemed authors from the email industry lined up to participate. 

Subscriber Management: How to Start, Maintain, and Break Up by Elizabeth Jacobi. Read it. 
Email Opt-Ins: It's All About Consent In the End by Matthew Vernhout. Read it here. 
Email Authentication 101: What It Is And Why It Is Important For Brand Reputation by Yanna-Torry Aspraki. Read it here. 
Why Blocklists Make Us Better Email Marketers by Andrew Kordek. Read it
IP Warming - Do It Right or Do It Twice by Amanda Jackson. Read it
Email Deliverability and Subject Lines by Dela Quist. Read it


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Email deliverability is the core of email marketing and email list cleaning is one of the most important elements of deliverability. According to OneSignal, “Almost 300 billion emails are sent per day, yet only 85% of legitimate emails reach their desired recipients”.

Great email deliverability starts with good data and relevant messaging to ensure your deliverability is on track. According to Chris Arrendale’s book,  Deliverability Inferno, “The biggest impact on improving the likelihood of reaching the inbox is a clean and up-to-date list.” 

Here are a few simple questions you should be asking yourself at the start of your deliverability improvement journey. 

  • Are you sending emails with relevant messaging to your subscribers? 
  • Did they give you consent to send to them? 
  • Is this email campaign what your subscribers signed up to receive?
  • Are you neglecting to manage your list properly which includes periodic list cleaning?

Failing to manage any of these challenges will impact your ROI resulting in fewer emails being delivered to the inbox than you are actually sending.

Deliverability is hard. That said, email marketers need to properly understand it in order to improve the success of their campaigns. To get you started, below is a list of 6 steps I’ve put together for you to use today that can immediately help improve your deliverability. 


1. Don’t purchase lists 

I get it. Email marketers and lead gen managers need to reach people fast. You're constantly being solicited by list providers and in a crunch to drive new revenue. You can get a massive list at an affordable price and that sounds great, right?  Nothing good comes from cheating the system and buying email lists. In short, you just shouldn't do it.

Here are 6 reasons why you should NEVER buy an email list: 

  • Good lists are never for sale
  • Most ESPs won’t let you send emails to a list you have bought
  • It will damage your sender reputation
  • You can come across as a spammer 
  • It violates rules such as the CAN-SPAM Act and GDPR
  • You can get blocklisted

There are other ways you can build a successful email list. 


2. Set up your IP and Domain Address


A. Enable IP and Domain Authentication for your email programs. 

IP Warming and Authentication are talked about a lot within the industry. But, there is surprisingly still a lack of knowledge on the matter. 

“IP warming should be done methodically, beginning with a low volume of your most engaged subscribers. Over time, that volume should slowly be increased in order to build your sending reputation, allowing mailbox providers the opportunity to monitor your behavior and determine whether you are a trustworthy sender”. 

- Amanda Jackson, Deliverability at Iterable, Webbula Deliverability Series Blog: IP warming - Do It Right or Do It Twice

It can be a daunting and time-consuming task. But, it is a very important step to complete before you start sending emails. 

B. Segment by different IPs and subdomains

Brands will often use the same IP and same Domain to send emails to different segments of people. However, by doing this, a mistake to one email list can end up affecting all lists. This is because many marketing automation subscriptions default to a shared IP. For example, if you are using the same domain for all of your emails and someone on your marketing list marks you as spam, the support and transactional emails that are being sent to customer lists will ultimately end in the junk as well.

It’s important to incorporate subdomains because if something were to happen to one, the rest of your subdomains won’t be damaged and you will still be able to reach the more important segments. Consider checking with your provider on the costs associated with a dedicated IP address and whether it's right for you. Otherwise, you could be looking at an impact on your deliverability.


3. Clean your lists with the right provider


A. How to choose the right provider 

Here’s the problem, virtually any verification company will “clean a list”. While simple email verification has been one part of an overall deliverability tech stack for marketers over the years, it's no longer enough. Why?

Email verification only determines whether an email address will be accepted by the email server, not if it is safe to deliver to. With an increase in spoofing, bot attacks, and other nefarious entities, using only simple email verification can negatively affect deliverability.

To keep your lists healthy, consider using a provider that performs email verification and email threat detection, like Webbula. Using Webbula before you hit send provides that extra layer of identification and groups email threats into reputation, fraud, delivery, and conversion categories (high-risk to low-risk threats) giving the decision to send solely to you. 

B. How often should you clean your list

It depends…

If you’re sending and reviewing your metrics on a regular basis, most will clean their list regularly. - ie: quarterly. 

If you’re bringing in an email address from protected forms and sending on a regular schedule then a best practice is to clean your lists annually. 

“But I’m not a spammer, so I shouldn’t have any deliverability threats hiding in my email database?”

Legitimate email marketers doing everything right, including following consent to communicate rules and utilizing an email verification tool, may still have these nefarious threats hiding in their deliverable email lists.

 - What kind of email threats should you be aware of?

Bots, Temporary Domains, Blocklisted Domains, and Duplicates are just a few threats you should be aware of. 

Bots: There are good, bad, and ugly bots: the good/bad are real ones who sign up/subscribe, purchase something and click and open your emails. 

There are good bots designed to protect the end-user against malware, spyware, and viruses. 

However, there are ugly bots that you want to keep off your list. At first, they open and click your links 100 times a day. Then they stay dormant in your email list without any activity after some time to record your content. 

An example would be if a competitor signs up for hundreds or thousands of emails in Yahoo, Gmail, Hotmail, etc., and uses those emails to enter into all of your forms, and sweepstakes.

Temporary Domains: These are made by people who want to sign up to grab that discount or coupon with an email address that only lasts a few seconds, minutes, or hours. 

Blocklisted Domains: These are email addresses that belong to organizations, associations, or networks that have been reported for spam and for which email delivery is blocked. Email can no longer be sent or received at that account after being blocklisted. 

Duplicate Emails: More than one of the same email addresses. 


C. Why You Need Email Verification + Email Threat Detection

Deliverability is complicated and, as noted above, there are many platforms that monitor email after the email campaign is sent. They monitor things like inbox placement, DMARC, and blocklists. Webbula Verification + Threat Detection leverages proprietary technology that alerts you to over 50 threats hidden inside deliverable email addresses before you hit “send”. We categorize these threats into different threat types including Reputation Threats, Fraud Threats, Deliverability Threats, and Conversion Threats. Marketers can utilize intelligence gleaned from our threat flags to improve their acquisition efforts and improve every aspect of their campaigns and transactional emails. 

Leveraging Webbula Verification + Threat Detection before sending will improve the use of deliverability platforms, will help deliverability teams isolate poor acquisition strategies, and ultimately enhance the performance of email campaigns. And, at the end of the day, improved email campaigns are the goal for all legitimate email marketers. Email Hygiene 

D. Protect Your Forms: Double Opt-In & Real-Time Verification

You may want to consider implementing ReCAPTCHA and adding double opt-in to your forms. Using double opt-in is a great solution because once a customer signs up for your emails, they will receive a confirmation link to continue the sign-up process. This is made to assure that real people are signing up for your emails and not bots.

The best way to ensure you catch bots before they enter your forms is by implementing a threat detection service that coordinates with your CRM, email service provider, or lead capture forms to ensure the best top-of-the-funnel-data quality leads are entering your lists.

A real-time email cleansing API is designed to quickly determine if the email being submitted is a valid working email address and not a bot. This will help decrease the fraudulent or inaccurate data submitted via your forms, protect your deliverability and sender reputation, and improve your campaign ROI. On the front end, it will create a better experience for your customers.

4. Tackle your inactive subscribers 

A. Develop an internal business definition of 'inactive'

Define inactives based on your company’s business model, customer relationships and lifecycle, and email program’s goals.

B. Determine the root causes of subscriber inactivity

Start by determining the time frame when the highest percentage of inactives start disengaging. This helps you understand what may be causing subscribers to go inactive. Some examples may be:

         - Within two weeks of opt-in: it was probably a discount, offer, or whitepaper they wanted.
         - If it was a high percentage after two months - your email program simply isn’t delivering on expectations.

C. Develop proactive strategies to minimize subscribers from going inactive.

Fix the problem: If it hasn’t been done in ages, update the opt-in page. Change email frequency, add segmentation, personalization, and automated messages based on behaviors or simply just improve the quality of your content.
- Manage Expectations: When they sign up, they expect to receive content similar to what they saw on your website. Make sure what you’re sending after they sign up is in a line with this. 
- A Re-onboarding track for subscribers going inactive: Rather than waiting until subscribers go inactive, put them into a "re-onboarding" program when their behavior indicates their disengagement.  This program is designed to convey your brand’s value proposition with special content, “surprise and delight” offers, and questions and links designed to capture preferences.
- The billboard effect: The point that Dela Quist, CIO and Founder of Alchemy Worx makes often if you know him, is that companies need to tread carefully when looking at inactives. Just because subscribers haven’t opened a message in a year or more, doesn’t mean those messages may not be leading to online or offline conversions. 


5. Segment your lists

Every business is different. Which means the way you segment your email list will differ from how someone else segments their list. This is why segmentation is so important - everyone is different. You wouldn’t send an email about snowboarding supplies to someone who lives in Hawaii. You may segment based on several criteria such as intent data, location, recent purchases, and more.


6. Pay attention to reporting and metrics 

Reporting by no means is a glamorous task, but keeping an eye on it will help build conversions and improve your ROI. You should not only focus on clicks, opens, and conversions, but also unsubscribes, bounces, complaints, and your reputation. 



These 6 steps are a great start to keeping your email lists in tip-top shape. If you’re looking for other ways to keep your database healthy think about these: 


Meet the Author


Jack Wrigley, VP of Partnerships at Webbula

Jack builds value in early-stage companies and new product categories through business and marketing 
strategies resulting in long term growth. He has built
companies and led teams in pioneering innovative
products and technology
solutions across dozens of industries most recently in email.





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