toothbrush and bubbles clean email list

Email List Cleaning Best Practices: Why, When, How, and What


It’s a new year, and like your personal life, you’re clearing your minds from the previous year, setting new goals, and trying new things, so why not do the same for your email marketing program?

We’ve all been there and know that achieving good open, click-through, and deliverability rates is a balancing act. There are many areas that make up good email deliverability, and one of the most important is list hygiene.  

Let’s break down everything you need to know about list hygiene in 4 ways; the why, when, how, and what, so you can quickly be on your way to a cleaner list in 2021.

Why should you clean your email list?

1. Data changes

The average email list depreciates by about 30% a year. People switch email providers, jobs, and abandon old emails, just to name a few reasons why. Quality matters more than quantity, and having a smaller lister is something you shouldn’t be ashamed of. Small but mighty fine. 

Cleaning your list regularly will help keep your spam complaints, bounce rates, and unsubscribes down and help keep your deliverability, open, and click-through rates high.

2. Your forms aren’t protected

If this is the case, who knows what’s coming in. To ensure that you’re only getting real leads or subscribers through your webforms rather than bots, spam traps, or typos, you need to put a real-time email cleansing API into place. This will not only help decrease the fraudulent or inaccurate data attacking your forms, but protect your deliverability and sender reputation, and improve your campaign ROI. On the front end, it will create a better experience for customers. 

3. Spam complaints

The reason why you clear your lists is to avoid spam complaints. Lesser spam complaints mean fewer deliverability issues.

4. Email deliverability and sender reputation 

A disengaged list results in poor email deliverability and a failing sender reputation; it’s a long line of issues and headaches if you do not regularly keep up with list hygiene. 

If your audience doesn’t like the emails, it’s as easy as a click of a button for them to report you as spam. Management Service Provider (MSPs) such as Gmail can punish you for poor list hygiene if you send irrelevant content to your users who haven’t opted in or have been engaged. 

5. Inherited a list in your new role

We’ve all been there once or twice, you’ve entered a new job, and you’re left with an email list you don’t know much about. There are so many questions you may not have the answers to; How did these emails come to the list? Are they purchased? When was the last time they cleaned them? 

The best way to answer these questions is to clean your list and determine what is good and bad before you send. 

6. Purchased lists

You should never buy an email list. In email marketing, quality always comes before quantity. Build your list organically, but if you have been guilty of purchasing lists or inherited one, cleaning your lists is necessary. 

You have no idea what type of emails are in that list waiting to ruin your deliverability, sender reputation and permanently block you from sending. 

7. Avoid spam traps

One important reason why you need to clean your lists with email hygiene is to identify spam traps. They aren’t easy to see because they open and click like real email addresses. 

Now, did you notice I mentioned clean with email hygiene? I say this because verification will tell you if those emails collected were valid or invalid. Sometimes the emails can look valid but could be a bot sign up, typos, or a spam trap. We’ll get more into detail about email hygiene and verification in the “What” section of the article. 

8. Avoid email blocklists

If a major blocklist sees spam being sent from your IP/domain, your emails can be blocked, and you could be delisted. The delisted process takes a few days or weeks, but your IP/domain will continue to be blocked until that process has been resolved. It’s a whole task you should avoid.

When should you clean email lists?

1. Transferring data between CRMs

Having bad CRM data can create a negative effect on your marketing campaigns’ ROI, kill sales productivity, and waste money. According to Gartner, “organizations lose $13.3 Million yearly average on poor data.” and MIT Sloan states, “employees waste 50 percent of their time coping with mundane data quality tasks”. 

2. Switching ESPs

The same process applies for switching from one ESP to another; clean your data! You’ll want to separate active from inactive subscribers. This allows you to create a reactivation campaign at your current ESP.

3. Adding or switching to a customer data platform (CDP)

Before you gather your data with a CDP, you’ll want to ensure that you maintain updated and accurate data. Whether you’re new to your role and inheriting a bunch of data sources that need to be organized, or you’re ready to discover new segments, build models, and deliver real-time personalization, cleaning your list should be high up on your to-do list.

4. Acquiring new emails

Anytime you gather new email addresses, it’s crucial to make sure they are legitimate. This helps you avoid any issues down the road. 

5. Running a re-engagement campaign

Before you start sending out your “we miss you” emails to your inactive email subscribers, clean your list to help you weed out spam traps and other threats. 

How often should you clean your lists?

In a perfect world, your email lists should always be in tip-top shape, but we all know it’s not that easy. We recommend list cleaning be done every quarter. Just like spring cleaning, changing your clothes around for each season, or cleaning up the leaves before the winter months, you should remember to clean your lists often. 

Implementing a real-time verification to your web forms is just another small way to help protect your forms from fraudulent addresses daily. 

What solution is best for you?

Email list verification or hygiene?

The cheaper option isn’t always the best option. If you still have threats in your list, even after cleansing with Email Verification, here’s why that is. 

As a marketer, you set up a verification and validation service to identify if the emails on your lists are valid or invalid, but often forget that spam traps, bots, and other emails can pass a simple verification test because they open and click like real emails. 

For example, complainers or screamers are people who report you to the FTPs. These are REAL people behind emails reporting you and causing you massive issues. Because it’s a valid email, it will pass a verification test. 

It’s a prevalent issue, and that is why we see senders who use verification still have deliverability, sender reputation, and blocklisting issues. 

Email Hygiene goes a step further to identify those malicious emails such as spam traps, honeypots, bots, moles, complainers, and much more. 

Determining whether you want to know if your emails are valid or invalid, or if you want to get down to the root of your email list problems, you’re going to need a more robust solution. That answer is email hygiene. 

Make email list cleaning a 2021 priority

Email list cleaning and verification is a smart move in 2021, especially for B2B marketers. Many people have changed jobs and companies, unfortunately, closed in the wake of the COVID-19 crisis and ongoing economic struggles. Data hygiene is one of 10 action items Email on Acid recommends in the special report, Email Marketing and the Next Normal. Download it for free to learn more.

If you’re stuck not knowing where to start when cleaning your list, we hope this article gives you some guidance on where to start and what solution is best for you. 

Webbula is the industry’s most comprehensive email hygiene service. We provide email verification and email hygiene to help marketers feel confident when they hit send, knowing active and inactive threats are identified.

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Author: Jenna Devinney

Jenna Devinney is the Marketing Specialist at Webbula. She manages social media, creates eye-catching content, and oversees web design. She's a jill of all trades writing a surplus of 100+ blog articles over three years in the email hygiene and data solutions space.

Webbula is the undisputed industry leader in Email Hygiene, Data Enrichment and Audience Targeting services. Check out to see what Webbula has to offer.

Author: Jenna Devinney

Jenna Devinney is the Marketing Specialist at Webbula. She manages social media, creates eye-catching content, and oversees web design. She's a jill of all trades writing a surplus of 100+ blog articles over three years in the email hygiene and data solutions space.

Webbula is the undisputed industry leader in Email Hygiene, Data Enrichment and Audience Targeting services. Check out to see what Webbula has to offer.

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