Email List Cleaning – Give Your Email Marketing a Fresh Start

SHARE article:

Karolina Petraškienė
Content Marketing Manager
Reading Time: 5 minutes

Sending out an email to your list of subscribers can feel like a little adventure.

You carefully select the subject line, brainstorm the content, and work hard to make your call to action as appealing as possible.

But then, the numbers roll in and … it’s not what you expected. Much of your audience hasn’t even received the email and the chance to see your amazing offer.

To make sure that doesn’t happen, we’re going to show you:

  • how to scrub your email list and why you should do it in the first place
  • how to remove invalid and hard bounce email addresses from your database
  • how to avoid the most common pitfalls of maintaining a clean email list
  • how to transform your email broadcasts from adventurous to warranted – because you’ll be hitting the mark every time.

Excited? So are we.

First off: why clean your email list?

Among the many reasons why your email campaigns can underperform, an email list that needs cleaning is a big one. Regular email hygiene helps email marketers to tackle two common issues:

  1. sending emails to inactive email addresses.
  2. Having a poor email deliverability rate and sender reputation which prevents emails from landing in customer inboxes.

Let’s take a closer look at each of them.

1. Email addresses tend to become inactive

Email lists naturally decline with time. Some studies show that in just 28 days, 4.5% of your subscribers can become unresponsive. Your list may also have spam traps (stale emails turn into these), fake emails generated by bots, etc. You can imagine how this can quickly snowball and turn a profitable email list into one that even Neil Patel couldn’t resurrect.

2. Poor campaign performance ruins your deliverability and sender reputation

Maintaining a clean email list helps you reach maximum deliverability.

Deliverability is a complex topic and consists of many components like the sender’s reputation, domain reputation, etc.—but it’s important to understand the fundamentals. For more detail, you can find a full guide to email deliverability here.


As you may know, every domain has its own reputation. When you send an email from your domain, the ISP of your recipient acts as a bouncer. It has one job and one job only: to let in the cool emails and throw out those stirring trouble.

What is an ISP?

An ISP (Internet Service Provider) is an organization that provides services for accessing, using, or participating in the Internet. There are many different kinds, but the ones you should know about are email service providers like Google, Yahoo, or Outlook. People who use them want one very simple thing: ZERO spam emails. So, it is very important for these companies that they let no spam email slip through their filters.

To help them determine which emails are good and potentially bad, they look at the sender’s domain reputation. If your domain’s reputation is good, you get in. Otherwise, you stay out.

This can be good news or bad news, depending on your current reputation.

But what this really means is that your domain reputation is not a fixed thing. Your ever-changing reputation is based on a number of factors: how many subscribers open your emails, click on your links, label them as spam, how many emails hard bounce, and how many simply get deleted (ouch, that hurts).

Obviously, you want to maximize the first part and minimize the second.

But how?

While there are many ways to improve your email marketing, cleaning your email list should be the top priority—especially for those who have an established email list.

Removing old, fake, and spamtrap email addresses will help improve your sender reputation and increase the likelihood of being a part of the cool emails that land in the inbox. This is why email list hygiene is so important.

As good as email marketing best practices are, if your emails are ending up in spam, great subject lines aren’t going to mean much. Clean your email list first!

When, and how often, should you scrub your email list?

The most important email list cleaning should be done before changing your ESP. There are several reasons why you should do that:

  • You won’t transfer bad contacts.
  • You keep your reputation intact (which is very important during the warmup process with the new ESP).
  • Your warmup process can be quicker (as you do not see poor metrics during the warmup).
  • You are only paying for active subscribers, not fake, bad, or inactive email addresses.

If you aren’t looking to change your email service provider then the answer is simple–do it sooner rather than later. As a general rule, you should clean your email list at regular intervals (we recommend once per quarter) AND also if you notice a sudden drop in your open rates. However, if you’re rapidly increasing new subscribers, a monthly check might be more appropriate.

How to clean your email list of bad subscribers

Email list cleaning and validations isn’t something difficult to accomplish, but it is important. Remember, inactive contacts spoil your overall metrics, decrease deliverability, and burn through your mailing credits.

  1. You should unsubscribe (not delete or remove) inactive customers by creating a segment and unsubscribing it.
  2. You should use an email list cleaning service for detecting spam traps and fake emails.

Both steps are vital when scrubbing your email list. Don’t worry, mail list cleaning services are generally affordable and provide great accuracy. If you use Omnisend for your marketing needs, your Customer Success Manager or support rep can help you with that.

List cleaning service at Omnisend

While there are a number of online services providing email cleaning, Omnisend offers one of the most comprehensive list cleaning services.

Our service allows you to upload a list of contacts and check which of them are bad email addresses, no longer used ones, contain typos, or, in some other way, might bounce or damage the sender’s reputation. Omnisend’s email scrubbing service applies artificial intelligence which constantly learns to validate email addresses. It has custom grammar checks for Hotmail, Yahoo, and Gmail emails.

This service allows our new customers to come to Omnisend with a cleaner list, achieve better results warming up, and protect their sender reputation.

Due to the nature of Omnisend’s cleaning process, we get as close to the true status of a particular email address as possible. This process not only checks the email address status at the moment of validation but also looks for historic data across a database of billions of email addresses.

However, it’s important to note that due to its nature, list cleaning does not get rid of 100% bad emails or inactive Yahoo email addresses from a list.

Wrap Up: Email Hygiene Best Practices

There is no point in sending emails to stale email addresses—let them go. Once your list is free of ghosts, you can again focus on improving communication with your audience.

So the main points to take away are the following:

  1. Poor list hygiene can result in poor email deliverability, costing you sales.
  2. If you are about to switch your ESP, consider email list cleaning to protect from spoiling your sender reputation.
  3. Regularly (once per quarter) scan your email list and unsubscribe unengaged (haven’t opened your email for three or more months) subscribers.
  4. Use email cleaning tools to remove spam traps, inactive email addresses, and ones with typos.
  5. Keep email engagement high by applying email segmentation and marketing automation more actively.
Get a personal 1-on-1 demo and see how Omnisend can supercharge your marketing!
Get My Demo
Karolina Petraškienė

Karolina is a writer, content marketer, and email enthusiast at Omnisend. When she's not curating articles, you can find her in the woods challenging herself in hiking boots or off-roading her bike.

Further Reading:

11 Reasons Why Your Email Goes to Spam
Email Deliverability Guide 2021: Common Issues and Best Practices
sender reputation warming cover
How to Use Sender Reputation Warming for Better Email Deliverability

Leave a comment

Your email address will not be published. Required fields are marked *