What is Email Scrubbing and how does it Boost Email Deliverability?

Email marketing is a powerful digital marketing tactic, the best email marketing campaigns have an astounding 4200% ROI. Your email subscriber list is one of your biggest assets. Unfortunately, not everyone on that list is an active or engaged subscriber. So maybe you need to scrub your email list?

Email scrubbing is removing bad, inactive subscribers and duplicate emails.

That way, you improve deliverability and can concentrate on subscribers who’re truly interested. Bad emails on your email subscription lists costs money. With email list scrubbing, your ROI increases as you’re making room for high-quality subscribers.

Lets look at everything you need to know about email scrubbing. That includes what it is, how it can help you, how to get it right, and the best email scubbing services that can help you on your way.

email verification results email scrubbing

Email Scrubbing: 3 Warning Signs

You spend time and money growing your email list. It makes perfect sense to take good care of your email list. But how do you know that your email list needs to be refreshed? Here are a few classic signs that your email list needs to be scrubbed:

1. Low Open Rate

Your email marketing metrics are the first place to inspect if your email list needs cleaning. If your open rates and click rates have declined over time, it’s probably because your list has a large chunck of people that aren’t interested. If your open rate is too low, it means you’d be better off cleaning your list from inactives. Send that email to someone who will. When people aren’t opening and clicking, you’re missing out on potential revenue.

2. Spam Complaints

Are your spam complaints too high? Getting flagged as spam is an email marketing problem. This is one of the more serious signs that some subscribers should not be on your list. 

Spam complaints are logged by mailbox providers like Yahoo and Gmail. If they find too many, they will start sending your emails straight to the spam folder—not just for the people who reported your messages as spam, but for everyone you send to. It’s also possible that a subscriber will mark your emails as spam because they don’t remember signing up. 

3. High Number of Unsubscribes

A rising number of people who no longer want to receive your emails is another cause for concern. Check to see the signup source, if any of the email addresses are invalid and scrub your list when you find them. You might also need to retarget your marketing efforts to make sure you’re reaching people who are likely to be interested in your services.

Here are three typical to keep an extra eye out for email list health and if you need email list cleaning services.

  • If you rent an email list, make sure to validate and clean it before sending any emails.
  • When you’re moving from one email newsletter software to another is a perfect time to scrub your list. It makes sure that you really start clean without anything contaminating your list.
  • When you’re trying to scale a business with email marketing, good email hygiene is a must.
  • Keep an extra eye out for the email going through your SMTP servers, like for instance are connected to WordPress.

Benefits of Email Scrubbing

Email scrubbing has multiple advantages, especially because disengaged subscribers offer none. Let’s see what a sparkling clean email subscription list will do. Not to mention strengthen your marketing strategy:

1. Reduce Costs

Every email you send has a cost attached. It’s not a huge amount per subscriber, but it’s not nothing either. And the numbers can really add up. So, if your list is full of invalid, duplicate addresses, or inactive subscribers, you’re basically throwing money away as those emails will probably never be read. 

Removing emails of unengaged subscribers will turn around the ROI of your email marketing campaigns. It also means that the same marketing budget is focused on people who are more likely to become customers or at least leads. This gives you more room to tweak your marketing strategy and push these subscribers down the conversion funnel.

2. Reduces Bounces and Spam Complaints

When you’ve spent time crafting a smart email marketing campaign, it’s very frustrating when the messages come bouncing back. If a lot of emails aren’t reaching their targets, the campaign isn’t going to be very successful! 

Plus, bounced emails affect your sender reputation just like spam complaints do. With email scrubbing services you will remove email addresses that often bounce, whether it’s due to a misspelled address or a full inbox. This will boost email deliverability for every email marketing campaign.

3. Remove Spam Traps

Spam traps are email addresses used to identify and monitor spam emails. ISPs (Internet Service Providers), anti-spam organizations, and companies use spam traps to lure spammers. Even if you aren’t a spammer, you can end up with spam traps in your contact list. And having an email like this in your contact list can cause your IP or domain to be denied. This has a severe impact on your sending reputation and email deliverability.

The best way to prevent spam traps is to regularly clean your email list. Most email list cleaning services will help identify and remove these from your list.

4. Increases Open and Click Rates

Post email scrubbing, when you’re sending emails to people who actually want to receive them, you will see a natural increase in your open rates and click rates. This is because these metrics are calculated as a percentage of the total emails sent.

Email scrubbing ensures that people aren’t marking your messages as spam anymore. This helps improve your reputation with email service providers as well as your deliverability rate. And, of course, better open and click rates mean more conversions and sales.

Prepare for Email Scrubbing

In a moment, we’ll take a look at the steps involved in email scrubbing. But before you get going, there are a couple of things you need to take care of.

1. Decide Which Lists to Scrub

It may make sense to start with your most active email lists, because they’re the ones driving leads and conversions. But the bigger gain is in the older lists—unengaged subscribers here may still count as part of the total. It’s best practice to scrub all your lists on a regular basis.

2. Figure Out Why Your Emails Bounce

Is this happening due to a simple misspelling in the email address, or something more serious? Bounced emails are divided into two categories: “hard” and “soft”. You can see which is which in Mailchimp’s “View Reports” section, for example. This will allow you to track down the source of the problem(s) and potentially do something about it.

A hard bounce indicates there’s a permanent error (maybe the domain name doesn’t exist) which means your emails will never reach that recipient. A soft bounce indicates there’s a temporary problem, but multiple soft bounces are also sign that the email is undeliverable. A list scubbing service often already knows this.

Guide to Email List Scrubbing

We’ve covered when you need to scrub your email list and we know the reasons why it’s a good idea. Now, let’s get down to the finer points of the email scrubbing process to get the best results when using email verification services:

1. Segment Inactive Subscribers

You need to identify the recipients you suspect of being inactive subscribers. Separate them from your active subscribers’ list. Your email marketing or scrubbing service will be able to create segments for you. Below is a screenshot of the MailChimp dashboard that lets you do this.

But what criteria should be used to identify inactive subscribers and verify emails? A good rule of thumb is that anyone who hasn’t opened your emails in 90 days can be considered inactive. These are people who haven’t gotten around to unsubscribing, but they’re not reading or acting on your messages either. This figure will also depend on the frequency with which you send out emails.

Mailchimp segment inactive subscribers dashboard

2. Identify Invalid Email Addresses

Your email subscription list is probably full of email addresses that are duplicates, spam traps or misspelled. We all know how easy it is to make a typo when entering an email address, and just one wrong letter or digit means the message won’t be delivered. And you have to watch out for spam email addresses, which may be collecting information for nefarious purposes.

It’s also a common problem in workplace communications to subscribe twice to an email list. If your list is longer than you thought, that’s probably because it contains at least a few duplicate email addresses. You need to remove these if you want to get a better idea of how well email marketing works for you. 

It’s hard to spot all of these issues manually, which is where email scrubbing services come in. NeverBounce, for example, helps you identify invalid email addresses so your email list is filtered and squeaky clean.

Neverbounce identify invalid emails email scrubbing

3. Re-engage for a Win-back

Once you’ve segmented your inactive subscribers, they deserve a check-in before you finally remove them from the mailing list. This is your last chance before the final goodbye to see if you can win them back. Check out the simple win-back email by Asana below.

Your ultimate attempt to re-engage has to be targeted. Send a personalized email with an incentive, such as a discount or a gift offer to entice them back into the fold. Directly ask them if they would like to unsubscribe, and it would be a great idea to ask them why they’re choosing to leave. Then you’ll have a better idea of how you can improve your messaging or services for the future. 

Reengagement email example Asana email scrubbing

4. Remove Email Addresses

You now know the email subscribers who don’t want to hear from you; you tried to win them back, and you couldn’t. It’s time to bid them farewell. And for good reason.

You have on your hands a bunch of active subscribers who will help you boost your business to the next level. Focus on them and remove inactive subscribers from your email list.

If you’re using MailChimp as an email cleaning service, just go to the segment you created for inactive users and click on “unsubscribe”. This will automatically remove all inactive users from the mailing list. All SaaS marketing automation platforms or email marketing services have a similar unsubscribe option.

However, it’s important that you don’t actually delete these contacts and their emails. You will find a use for them later, so maintain them in your database. You can try another marketing strategy for these people, such as social media or using your contact centers to try cold calling.

Mailchimp remove email addresses unsubscribe dashboard

5. Determine Reasons for Low Engagement

You have removed the subscribers who didn’t want to engage, but did you find out how they arrived at this point? If your initial targeting was spot on, it’s in your favor to figure out why and when the recipient lost interest. This helps you hone your email marketing strategy to ensure other subscribers don’t go the same way.

It’s possible that the lack of a custom domain name will affect your email deliverability. Service providers are partial to emails that have a custom domain name and not a generic one like gmail.com or hotmail.com. There are services that offer free email with custom domain names to help you with this.

3 Best Email Scrubbing Services

It’s a laborious task to clean up your email list manually. You’ll definitely need the help of email scrubbing software to save time and ensure you only remove the correct addresses from the list. We collected the best email list scrubbing services. Here’s a short list:

1. Bouncer email validation

Bouncer email validation verification result review

Bouncer is an email verification service. It will help you find misspelled, duplicate, spam, and risky email addresses. It will also check for all kinds of bounces caused by expired or non-existent domain names. 


  • It’s free to get started
  • Highly accurate bulk email verification
  • Integrations with popular tools
  • Pricing is great, and option to choose pay as you go


  • Free email verification only shows basic information

Bouncer offers 100 credits for free with access to main features. The pay-as-you-go pricing costs $0.008/email if you’re checking 4,000 emails. When the number of emails goes up, the price/verified emails fall.

Bouncer is already one of the best value email scrubbing tools. And we got an additional 25% discount for our readers. Just sign up through this special link here to get the discount.

Try Bouncer for free here or read our full review

2. ZeroBounce

ZeroBounce is another popular email verification service. It helps you learn about email typos, spam traps, and abusive email accounts that can lead to unwanted signups. It’s a powerful email scrubbing tool that provides a clean database with bulk email verification and a blacklist monitoring service.


  • Highly secured
  • Allows you to score subscribers based on interactions


  • Not the best if you’re looking for a cheaper option
  • The support provided is not as good as with other services.
Try ZeroBounce for free here

3. KickBox

Kickbox verifies every email address on your list to maximize inbox placement. This email verification service validates emails without sending any emails and offers real-time email verification, bulk email list cleaning, and real-time API support. It also connects with most email marketing automation services and Zapier. 


  • Quick and easy to set up and navigate
  • Email validation at signup
  • GDPR compliant with US and EU servers


  • More expensive than other services

Compare the prices of Kickbox in our overview of the best email list cleaning services

Try Kickbox for free

Using an Email List Cleaning Service: When Less is More

Your engagement rates will rise if you clean your email list to contain only high-quality subscribers. Email list scrubbing removes unengaged or even harmful subscribers. Those who ruin your email marketing efforts. Clean your email list a few times a year.

Frequently Asked Questions (FAQ)

What does it mean to scrub a list?

To scrub a list means to clean it and reduce its size by removing inactive (or “pointless”) subscribers who don’t engage with you and are never likely to do so. Scrubbing also lets you remove invalid and duplicate email addresses from your list.

How do you scrub a mailing list?

To scrub a mailing list first, you segment the subscribers on your email marketing platform into “active” and “inactive” categories. Then, you identify any invalid or duplicate email addresses using email verification tools, like Bouncer, ZeroBounce, Mailercheck, or Mailfloss. Next, you send a re-engagement email to all inactive subscribers in the hope of winning them back, usually with an incentive. Anyone who doesn’t click on that email can be removed from your mailing list. 

How often should you scrub your email list?

Initially, you should scrub your email list every 3 months. Once you have developed a practice of scrubbing your email, you won’t need to do it so often, and it won’t be such a large task every time. Remember that the quicker your email list grows, the more often you’ll need to scrub it.

How much does it cost to clean an email list?

Charges for an email list cleaning service vary depending on the service you use and the size of your email list. For example, Bouncer gives you 100 free credits to get you started with email scrubbing. Some services offer a pay-as-you-go scheme, while others offer a range of monthly pricing plans. Bouncer, MailerCheck, ZeroBounce, and Mailfloss offer monthly and credit-based pricing.

How do I clean up my email database?

The easiest way to clean your email database is using email validation software, like Bouncer, MailerCheck, ZeroBounce, or Mailfloss. Connect your email marketing software to sync your email database and clean it. Or upload your email list to the email validation tool, run it and export the cleaned results. You should also make sure that every email you send has an unsubscribe link for people to click if they want to, which will help your company seem more trustworthy.

About Jenna Bunnell

Jenna Bunnell is the Senior Manager for Content Marketing at Dialpad, an AI-incorporated cloud-hosted communications platform. She is driven and passionate about visualizing how content can be presented in creative and comprehensive ways.

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