It’s scary to send a mass email campaign to a freshly bought list.

How do you know they’re safe to send? How can you ensure it won’t irreversibly damage your sender reputation?

Your list could be riddled with fake and low-value email addresses, which end up costing you time and money filtering through them. Even if your emails aren't spam, there is always the fear when you push 'send' on a bulk email campaign that your bounce rate will be through the roof.

If you've been compiling contacts for years but never touched your list, it's likely out of control. 37% of email addresses change annually, and if you aren't regularly managing your data, then your lists will quickly end up full of outdated information. 

Cleaning up your email list will ensure that you're working with an accurate list of hot leads and not wasting money, time, or resources marketing to an unclean database. In this article, we’ll walk you through email list cleaning best practices and services you can use to help you.

Want to see how clean your list is? Request your free data quality check.

What does cleaning an email list mean?

Email list cleaning is the process of removing inaccurate and inactive contact data from your email database. If you bought an email database, cleaning them ensures you don’t jeopardize your IP reputation by sending mass emails that bounce or go to spam.

If you’re cleaning an opted-in database, it involves being responsive to your contacts' preferences and eliminating anyone who is no longer engaging with your emails. Cleaning an email list also means getting rid of inaccurate information, which could include:

  • Fake emails

  • Outdated email addresses

  • Typos

Email list cleaning is an important part of email list management, which is the overall workflow of keeping an email list that is comprehensible, standardized, and most of all —usable and trustworthy.

Regular email list hygiene  means you’re practicing care with your email data, and your campaigns will reward you.

There are two ways that you can clean your email list: manually or automatically. This article will look at how to manually clean up your email list, email list cleaning tools, and the best email list cleaning services.

Clean your email list with this 15-point email hygiene checklist

What happens if you don't clean an email list?

Continuing to use your unclean email lists is risky business. A few email bounces may not seem too concerning, but reduced deliverability contributes to a whole string of other problems.

The goal of all your email marketing campaigns is to get information in front of eyeballs, maybe even a sale. You will struggle to succeed with your email marketing efforts without a clean email list. 

Below are some of the main issues that you will encounter due to not cleaning your email list.

1. Damage you IP reputation 

Using an unclean email list when sending your marketing campaigns can end up severely damaging your IP reputation. If you are unknowingly sending emails to spam traps it will ding your IP address. Other factors that will damage your IP reputation include:

  • Recipients flagging your emails as spam

  • Low open rates

  • High bounce rates 

2. Annihilate your deliverability rates 

If there is bad data in your email list then your email deliverability rate will suffer. If you have fake emails in your database they will hit a hard bounce, but that’s only a small part of the problem. Deliverability issues lead to low open and click-through rates, which will reduce your overall conversions. 

3. Increase email marketing costs 

Most email marketing platforms will charge you based on how many contacts you are sending to. While a few invalid emails won't cost you a considerable sum, high volumes of email bounces can add up quickly. MailChimp will automatically remove hard bounces, but won’t remove soft bounced emails until they have bounced 7 times. Additionally, when your emails aren’t reaching potential leads then you’re missing out on tons of conversion opportunities.

4. Spam complaints

If email providers, like Gmail, believe that you are sending out spam, they will automatically send your emails to the junk folder. So, why would they think that you're spam? When someone receives an unsolicited email from you or no longer wants to receive your content, they can report it as spam. If you receive too many of these spam complaints, then your emails could be blocked by ISPs, meaning that even those who want to receive your emails might not.

5. Unsubscribes

Continuing to use unclean data lists can result in warm leads unsubscribing to your emails. Personalization and segmentation is the key to marketing success. When contacts subscribe, they are looking to receive tailored, high-quality information that is relevant to them. Sending out generic emails that provide no value will result in unsubscribes. If contact data has incorrect information or missing fields, then you're unable to effectively target your contacts with information.

Comparing open and click rate of segmented vs non-segmented emails

3. Email bounces

High email bounce rates will also negatively impact your email deliverability rate and damage your domain reputation.

4. Missed connections/loss of leads

Someone might be extremely interested in your product and has expressed their interest using an online form. Unfortunately, they made a typo when filling it out, and now you're unable to connect with them. The @ sign may have been misplaced, or instead of '.com,' they may have written '.con.' Simple errors are easy to correct during the data cleaning process, but if you're not cleaning it regularly, then those potential leads will end up going cold.

How does your email list get so dirty?

It's essential to understand what is contributing to bad data in your email database. How is it getting in there in the first place? Knowing the most common culprits will allow you to take steps to reduce the amount of inaccurate data that ends up cluttering up your lists.

1. Human error

Human error is the number one way that inaccurate data ends up in your email lists. It is inevitable. Whether your team is inputting data manually or contacts are inputting their details into an online form, there will always be errors. Human error can lead to:

  • Typos

  • Information entered into the wrong field

  • Missed fields

  • Inconsistent formatting

Having processes in place helps to reduce the amount of bad data that ends up in your email list as a result of human error. These could include strict data entry guidelines for staff around formatting for each field and constraints around how contacts can enter their information. 

Most CMS platforms will allow you to customize fields in your contact forms, which can detect invalid emails or data entered into the wrong field. You can also make it mandatory to fill out specific fields to submit the form.

2. Data decay

The data in your email list may have been clean once upon a time but has fallen victim to data decay. Data decay is the gradual loss of data quality within your email database due to changing contact details. Email addresses, phone numbers, postal addresses, and job titles are always changing, and most people won't inform you of this change.

Over time, your list will naturally become outdated, so make sure that you are regularly cleaning and updating your data sets. You will also need to implement an email list verification process to ensure that contact emails are still valid.   

3. Duplicates

There are a few different ways that duplicate emails can find their way into your email list. Contacts may enter their details more than once when opting in for your email list or downloading a lead magnet. Alternatively, staff may manually enter contact data without checking to see if someone is already in the list.

4. Loose formatting

If you don't have formatting rules for your email database, your data will become dirty quickly. For many fields, there are a variety of different ways that you could enter information. If you don't have rules around which format you want, your staff and contacts will enter details in different ways. Here are some examples of how the same piece of data can have multiple formats:






Mr. B Smith

Brandon Smith

Brandon T. Smith


55 Third St.

55 3rd street

55, Third Street

Implement strict parameters around how data is entered, including restrictions on contact forms that encourage people to enter information in the correct format. 

Formatting is extremely important in your email list since it will allow you to find the data you need quickly, and also ensure its accuracy. For example, if you’re sending out special offers to contacts on their birthday then all birthdays to be in the same format. If they aren’t, you’ll end up sending things out on the incorrect date. 

How to know when you should be cleaning up your email list

So, how can you tell when it's time to invest in email list cleaning? If you have never cleaned your email list before, then the answer is right now! It’s never too early for email list cleaning and validation since no dataset is perfect. 

Often you can see that your email list is disorganized just by looking at it. But the best place to identify the state of the data in your email list is in your email marketing statistics.

Have a look at the analytics from your previous campaigns to see if you can notice any patterns. The most important metrics to look at should be:

  • Unsubscribes

  • Open rates

  • Click-throughs

  • Spam complaints

Compare your metrics against data-driven email marketing benchmarks in your industry to see if you notice any staggering differences in one area or another. If you see that your metrics don't stack up or that there has been a constant decline, then it's time for email list cleaning.

Email marketing benchmarks

If contacts aren't receiving your emails, aren't opening them, and aren't clicking through,how can they convert?

If you never touch the food inside your fridge, it won’t be long before you have a rotten situation on your hands. The same applies to your #emaillist. @tye_io looks at how to clean your email list and the best email list cleaning services on the market:

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What should you do before cleaning an email list?

Before cleaning your email list or using email list cleaning tools, do a few key things to prep your list.

1. Check for soft and hard bounces

Not all bounced emails indicate an invalid email address. Before you purge contacts from your email list, check for soft and hard bounces. Sometimes there could be a temporary deliverability issue impacting your emails going through, but the contact details are still valid. That’s called a soft bounce. Most ESPs (email service providers) will try sending it through again, and next time it will likely go through.

Hard bounces indicate that either the email address no longer exists, is incorrect, was a disposable email or that the email server is blocking your campaigns' delivery. Unless you have another means of reaching the contact to update the email, then it's best to remove those addresses as part of the cleaning process.

email bounce rate statistics

1. Send out a re-engagement email campaign

Another critical step before cleaning your email list of inactive subscribers is to send out a re-engagement email campaign to see if you can salvage those contacts. Segment inactive subscribers and try to bring them back using an email drip campaign. 

The first email should ask subscribers if they still want to hear from you. Make it super basic and easy to engage with, including large 'yes' and 'no' buttons, and that's it. If the contacts choose 'no,' then you can remove them from your list.

If contacts opt-in with a 'yes' on your re-engagement email campaign, then you can begin to nurture them again with an incentive or special discount. It's important to pique their interest once again while you are still fresh in their mind.

Email list cleaning tactics

Now onto the juicy stuff – how to actually clean your email list. Whether you're going to tackle it on your own or use an email list cleaning service, it's still beneficial to know exactly what tactics are used when cleaning your email list.

1. Segment your audience

Segmenting your contacts is an integral part of cleaning your email list. Segmentation will allow you to better personalize your email campaigns based on each of your contacts' unique attributes, along with where they are at in your sales funnel. 

You can have your contacts set specific communication preferences, such as how often they want to hear from you and what they want to hear about. You can also segment them based on demographic information that they’ve provided, geographic location or the stage they are at in your sales funnel. 

Chart showing how data-driven email marketing helps with segmentation

2.Start by scrubbing active lists

When you start email scrubbing, start with your most active lists. These lists are the people you engage with the most frequently and send the highest number of emails to. You could have one bulk email list or multiple segmented lists to send email marketing to, so work through them from most active to least active.

3. Remove/merge duplicates

As we mentioned above, there are various ways that duplicates can end up in your email list. When you’re sending double messages you will reduce your ROI. Not only will it cost you more, but contacts who may have been interested initially might put you in their spam folder or blacklist you when they keep receiving two of each email.

4. Remove spam email addresses

You can usually identify spam email addresses just by looking at them, but not always. That said, you likely don't have the time to manually look through your entire email list to find the spam traps

Spam emails typically look like nonsense, but they can also look remarkably close to common company names or words, so they appear legit. Some examples of what spam emails might look like might include:


Many email validation services can do it for you.

5. Correct obvious typos

Large email lists (especially those left to grow unsupervised), tend to come with typos. It can be hard to determine which are typos and which are legitimate. You can correct obvious typos, while unobvious typos are more challenging because you can't just assume that they are incorrect. A name might look strange, but that doesn't mean that it's an invalid email address. Here are some examples of obvious vs. unobvious typos:




6. Make sure data is in the correct field

Data likes to make its way to the entirely wrong field. If an email address ends up in the postal address field, then the contact won't be receiving your email marketing. Data can end up in the wrong field during bulk contact imports or when a staff member is populating the information. Contacts can also fill their details into the incorrect field when using onsite contact forms. Everything must be in its correct place so you can use the data effectively.

7. Make sure all fields are consistent

Consistency is key when cleaning up your email database. Are you going to use capitals for names or not? How do you want to format information like birth dates or postal addresses? The format you choose is up to you, but make sure that all the fields are consistent.

Why should you use an email list cleaning service?

Cleaning your email list yourself is extremely tedious. Depending on your email list's size and condition, it can take multiple staff members hours, days, or even weeks to get through all your contact data to clean it up. And even still, it's unlikely to be perfect since human error is always inevitable.

Using an email list cleaning service is hugely beneficial, especially when compared with manual data cleaning. Here are just a few of the many benefits of using email list cleaning tools or scrubbing services:

  • Block potential fake emails

  • Bulk email verification (which is excellent for massive email lists)

  • Fix common typos

  • Email validation

  • Populate first names automatically

  • Save hours of staff time

  • Make email marketing more scalable

  • Aids in personalization

  • Fix inaccurate emails, instead of just deleting them, so you lose less data

The automation provided by email list cleaning tools is game-changing when it comes to saving time on cleaning up your data.

The best email list cleaning services

There are many email list cleaning services and tools out there, but these three are the best on the market:

1. tye

screenshot showing how tye data cleansing works

tye is the ideal email list cleaning service for SMBs who want a powerful, user-friendly cleaning tool that's completely hassle-free. All you have to do is upload your data to tye, and it will clean it for you immediately. tye goes a step further than just cleaning your data; it also normalizes it so that automation tools can accept your import with errors like the MailChimp Omnivore warning.

Best features:

  • Populates genders

  • Combines individual lists into a standardized format

  • Removes invalid email addresses

  • Removes duplicates

  • Identifies salutations

2. Xverify

preview of xverify for email verifiaction

Xverify is an intelligent email verification tool that automatically informs users whenever they enter any incorrect data into its interface. It also assists users in correcting errors with automation features and an email checker to ensure your emails are deliverable..

Best features:

  • Email verification

  • Protect against fraud

  • Removes invalid data

  • Domain auto-correction

  • Boosts email deliverability

3. Snovio

Preview of Snovio, an email verification tool

Snovio is an email list cleaning service that boosts your email open rates and protects your campaigns against deliverability failure. You can build drip campaigns and then send them directly to your contacts. That means that you no longer have to manually create emails since the content will automatically be sent out to your contacts at a predetermined time.

Best features:

  • Email finder to locate email addresses for leads

  • Integrates with your API

  • Tracks email performance

  • Email validator

What to do after email list cleaning?

Cleaning your email list is just the first step. Once your list is clean, practice consistent email list hygiene to keep it healthy. You can never entirely prevent bad data from ending up in your database, but by cleaning your list regularly, you will ensure that you're not missing out on potential hot leads and conversions.

Want to see what percentage of your list can be cleaned? Request your free data check.

Clean your email list with this 15-point email hygiene checklist

Markus Beck

Markus Beck - January 5, 2021

CEO with a passion for data relationships. Markus is half Finnish, half Austrian & fully committed to helping businesses keep bad data from ruining great relationships. Process Engineer by training, with digital marketing & project management skills from previous jobs.