Does Email List Cleaning Help or Hurt Your Bottom Line

Does Email List Cleaning Help or Hurt Your Bottom Line?

Does cleaning your email list really help you or not?

Today, we are going to use two real-world case studies along with 3rd party data to answer this question.

Many email marketers from all over the world have been debating this. It’s time to put this issue to rest.

So buckle up and get ready to finally be given a data-backed answer.

Before we get into the case studies, we need to figure out if having inactive subscribers actually harms your email marketing…

Does having inactive email subscribers harm your email marketing?

Let’s walk through this together…

Major email service providers (ESP) like Yahoo, Gmail, AOL, and Outlook are on record stating they use engagement and spam traps as part of their algorithm to determine whether to deliver your emails to your subscribers.

According to Datanyze, 70.1% of emails used are Gmail which makes them the leading ESP by a wide margin:

Datanyze ESP Market Share

Sri Somanchi who was on the Gmail Anti-Spam Team was asked how Gmail handles email deliverability while on a panel at the Email Evolution Conference…

Here’s what he said, “Gmail takes email engagement very seriously.”

Sri didn’t go into technical details about Gmail’s algorithm because Google doesn’t want people to try to game their system, which makes total sense.

(Damn you blackhat SEO people for ruining it for all of us. I kid I kid. Well not really.)

The statement above by Sri Somanchi confirms that Gmail uses engagement as a deliverability metric.

Since we know engagement is one of the important email deliverability metrics used by Gmail, you may be wondering…

How does Gmail measure your email lists engagement?

Here is a list of things all major email service providers including Gmail use to measure engagement:

  • Do your subscribers open your emails? How frequently?
  • Do your subscribers reply to your emails?
  • Do they open and click your emails, or delete and ignore?

I’m sure you’re getting antsy. I promise the case studies are coming up soon. There is just one more thing you need to know first…

Have you heard of spam traps before?

Spam traps are email addresses that have shown no logins or activity for an extended period of time.

Keep in mind this is based on your subscriber’s activity from all emails they receive, not just yours. Each ESP has a different timeframe for labeling an email address a spam trap:

ESP SPAM Trap Timeframes

Ok, based on what we know so far having inactive subscribers that are not engaging with your emails is a bad thing.

Why should you care though? There can’t possibly be that many people on your email list who aren’t active, right?

I guess we better look at some more data…

According to Epilson, 42% of subscribers are inactive for 12 months or more per email list:

Epsilon Email Subscriber Activity Q2 Oct2013

See where I’m getting at here?

Having spam traps on your email list is very common. Just think about it…

Do you still use that Hotmail account you created 10 years ago? Ever created a new email address and completely abandon your old one?

If you don’t clean your email list regularly how will you ever get rid of these spam traps or inactive subscribers that are hurting your deliverability?

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Now that you have a good foundation of how ESP’s measure email deliverability, let’s take a look at the results two companies had after implementing a list cleaning strategy…

Case Study #1

The Tennessee Department of Tourist Development had a 500,000 person email list.

They knew their list was being dragged down by low-quality leads, so they decided to run a re-engagement campaign to clean their list.

This campaign was run 2 times over a 2 year period.

During the first campaign, 240,000 emails were labeled as low quality and put through their re-engagement email series.

Out of the 240,000 emails, 4,000 of them were added back to the main list, and the rest were deleted.

If we do some quick math, that’s 500,000 total email subscribers minus the 240,000 low-quality leads.

That leaves a total email list size of 260,000.

Then we have to add the 4,000 emails that were added back to the main list (4,000+260,000= 264,000). Bringing the total list size back up to 264,000.

The Tennessee Department of Tourist Development stated they were getting an 11% open rate at this time.

If we take the 264,000 emails times it by the 11% open rate, we get 29,040 emails opened.

After 2 years of list cleaning, the company were receiving a 13% open rate. That’s a 2% increase in their open rates.

Doesn’t sound like much huh?

If you take the same list size, they had (264,000) with a 13% open rate instead of 11% you get 34,320 opens.

That’s 5,280 more opens just by getting a 2% bump in open rates.

Case Study #2

JustAnswer is an online service that allows you to speak with experts such as vets, lawyers, doctors, tech support and home improvement.

Their newsletter was receiving a lot of SPAM complaints, so they decided to clean their list to improve email deliverability.

JustAnswer ran a re-engagement campaign to everyone on their list who was not active for the past 90 days.

Only 17% of their email list engaged with their emails over that 90 day period.

They moved the other 83% to a different email list that was on a different IP address.



Moving inactive subscribers to a different email account on a different IP address will allow you to continue emailing inactive subscribers without harming your main accounts email sender reputation.

Using a different from name along with this will be even more effective. You can buy different a different domain suffix like .co, .net, .org or whatever else you feel comfortable with.

For example, instead of sending from [email protected] you can send from [email protected] to your inactive subscribers.

After 3 months they got a 207% bump in engagement from their email list, their SPAM complaints reduced by 84%, email open rates increased by 46%, and their click through rates grew by 500%.

Other Benefits To Email List Cleaning

Improved Email Sender Reputation

ESPs like Gmail, Yahoo, and AOL use a combination of different metrics to decide whether to deliver your emails to your subscribers.

They don’t publicly state how much weight is given to each metric, but they have stated that open rates and engagement are metrics they use.

As shown in the two case studies, cleaning your list improves both open rates and engagement.

It’s clear that improving both will increase your email sender reputation and help you get more emails delivered to your subscribers inbox.

Accurate Email Data

When you leave a bunch of inactive subscribers on your email list, it completely throws off your data and makes it difficult to determine what’s actually working with your email list.

Here’s an Example:

You have a 10,000 person email list. Then you send an email to an offer.

You get a 5% open rate, a 50% click through to the offer, and 5% of the people who clicked through purchase a $27 product.

That means 500 people opened your email, 250 people clicked on the offer link and 13 people purchased.

Based on these numbers you earned $351 (13 x $27=$351). Your earnings per email subscriber on this offer is $0.0351.

With just a 5% open rate you may be thinking that either your list wasn’t that interested in your offer or your email copy wasn’t very good.

Remember that Epilson study we talked about earlier that says 42% of email subscribers on email lists are inactive for 12 months or more?

Let’s do the math for an email list that was cleaned. 42% x 10,000 = 4,200 inactive email subscribers. 10,000 – 4,200 = 5,800 active email subscribers.

If you send out the same exact email with the same numbers 500 opens, 250 click throughs, and 13 sales on a $27 product.

Your open rate is now 8.6%, and your earnings per email subscriber are now $0.0605 which is 58% higher.

Imagine making this mistake on every single promotion throughout an entire year. Your email data will be even more inaccurate.

You would be making decisions based on bad data.

For fun, let us take a look at how off your data would be if you ran just 2 promotions like this per month with the same exact results for an entire year.

Non-Cleaned List Earnings Per Subscriber: $0.0351 x 24 promotions = $0.84

Cleaned List Earnings Per Subscriber: $0.0605 x 24 promotions = $1.45


Lower CRM and Autoresponder Costs

Most CRMs and Autoresponders charge based on subscriber count or the number of emails sent. Some even charge you multiple times if a subscriber is on multiple lists.

If you’re using a CRM or Autoresponder that charges this way, cleaning your list could place you on a lower plan to cut your costs as it did for the Tennessee Department of Tourist Development.


Well, there you have it, ladies and gentlemen.

After reading both of these case studies, you now know that email list cleaning does improve your bottom line and your email marketing performance.

Your Action Plan

Start identifying low quality leads on your email list. If you don’t know where to start, I teach a simple 5 step process on “How to run a re-engagement campaign to your unresponsive leads” that you can follow.

Share your opinions and questions by commenting below. We’d love to hear what you thought about this content!

About The Author 

Brandon Shelton is the Founder of Mechanical Marketing (a SAAS and digital information publishing company) who loves studying marketing and playing basketball.

He has helped grow ClickMagick to a 7-figure SAAS as a partner and Chief Growth Officer, CMO at Gearbubble (a 8-figure/yr ecommerce SAAS) and is the Founder of LeadShield.

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