Email List Scrubbing 101: Definition, Purpose, Steps & Tools

Learn what it is email list scrubbing, why it's crucial for marketers, and how to effectively clean your list for better engagement and deliverability.
Email list scrubbing, though often overlooked, plays a critical role in any successful email marketing campaign.

In simple terms, email list scrubbing is the process of removing inactive and invalid email addresses from your subscriber list. This actually boosts your email deliverability and makes sure your message gets to the right people - those active and engaged subscribers.

In this guide, we'll cover everything you need to know about email list scrubbing - from its definition and purpose to the steps involved and the tools available.

So, let's dive in!

What is Email List Scrubbing?

Email list scrubbing, also known as list cleaning, involves removing unengaged, inactive, and undeliverable email addresses from your mailing list.

The process ensures that your marketing efforts reach your audience effectively, improving overall email campaign performance.

Additionally, inactive subscribers are often pruned from the list to improve engagement metrics and maintain high deliverability rates. Scrubbing services may also verify the validity of email addresses and ensure compliance with anti-spam regulations like the CAN-SPAM Act or GDPR, safeguarding sender reputation and adhering to legal requirements.

Marketers can improve campaign performance, increase open and click-through rates, and cultivate stronger connections with their audience by streamlining the list to only active, engaged subscribers.

Moreover, maintaining a clean email list improves deliverability, reduces the risk of being flagged as spam, and upholds the integrity of the sender reputation across various email service providers.

What is the Purpose of Email List Cleaning?

The primary purpose of email list cleaning is to ensure that your email marketing efforts reach their intended audience effectively.

Scrubbing your email list regularly removes invalid, outdated, or inactive email addresses that could otherwise harm your deliverability rates.

This process helps maintain a clean and accurate list of subscribers actively engaged with your content, thereby increasing the likelihood of your emails being opened, clicked, and acted upon.

Additionally, email list cleaning helps protect your sender reputation. Sending emails to invalid or inactive addresses can damage your reputation with Internet Service Providers (ISPs) and email clients, leading to your messages being marked as spam or even causing your domain to be blacklisted.

Keep your list clean and only send emails to engaged subscribers to maintain a positive sender reputation, ensuring that your emails are more likely to land in recipients' inboxes than their spam folders.

Signs That Your Emails List Needs Cleaning

Signs That Your Emails List Needs Cleaning

Your Open Rates Are Decreasing

A significant decrease in open rates often indicates that your emails are no longer relevant or interesting to a portion of your audience.

This decline could originate from various factors, but a common culprit is having inactive or disengaged subscribers on your email list.

Over time, subscribers may lose interest in your content or change their email addresses without updating their information. As a result, your emails fail to resonate with your audience, leading to fewer opens.

A decrease in open rates can also mean that your emails end up in the promotions or, worse, the spam folder. In this case, besides cleaning your email list, you might need to warm-up your email with an email warm-up tool to recover your health score and sender reputation.

Regularly clean your email list to identify and remove inactive subscribers, ensuring that your open rates accurately reflect your content's engagement level.

Your Emails Are Going to Spam

Having your emails consistently land in recipients' spam folders is a serious issue that can significantly impact your email deliverability and sender reputation.

This problem often arises when you send emails to invalid, outdated, or inactive email addresses, triggering spam filters.

Additionally, if your email content triggers spam filters due to certain keywords or formatting, it can also result in your emails being marked as spam.

Regularly cleaning your email list helps mitigate this risk by ensuring that your list only contains active and engaged subscribers with valid email addresses.

This, in turn, improves your sender reputation and reduces the likelihood of your emails being flagged as spam.

As stated before, you need to start warming-up your email immediately.

Your Sender Reputation is Declining

Email service providers track your sending habits and audience engagement. A declining sender reputation can block or filter your emails into spam.

Several other factors can contribute to a decline in sender reputation, including high bounce rates, frequent spam complaints, and low engagement rates.

If ISPs and email service providers perceive you as a sender with a poor reputation, they may start filtering your emails into recipients' spam folders or even block them altogether.

Regularly monitoring your sender reputation metrics and taking proactive steps to address any decline, such as cleaning your email list and sending relevant, engaging content, is essential for maintaining a positive sender reputation and ensuring that your emails reach your subscribers' inboxes.

Your Emails Are Bouncing

A high bounce rate, especially from hard bounces (permanent delivery failures), clearly signals that your email list contains many invalid or closed email addresses.

Bounced emails happen when messages cannot be delivered to recipients' email addresses for various reasons, such as invalid or nonexistent addresses, full mailboxes, or temporary server issues.

Both hard bounces (permanent delivery failures) and soft bounces (temporary issues) can negatively impact your email deliverability and sender reputation. Ignoring bounced emails can damage your sender reputation and may result in your domain being flagged as spam by ISPs.

Regularly cleaning your email list to remove invalid or inactive email addresses is crucial for reducing bounce rates and ensuring your emails reach your intended recipients.
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Benefits of Email Scrubbing

Email scrubbing offers several significant benefits for email marketers and startups looking to optimize their email marketing efforts:

  • Improved deliverability: Email scrubbing improves delivery rates by removing invalid, outdated, or inactive email addresses from your list. This ensures that your emails reach your subscribers' inboxes rather than being bounced back or marked as spam, ultimately increasing the likelihood of engagement and conversions.

  • Enhanced engagement metrics: A clean email list consists of active and engaged subscribers who are genuinely interested in your content. Scrubbing inactive or uninterested subscribers improves engagement metrics such as open rates, click-to-open rates, and conversion rates. This allows you to focus on nurturing relationships with subscribers who are more likely to interact with your emails and take desired actions.

  • Protection of sender reputation: Maintaining a positive sender reputation is crucial for email deliverability. Email scrubbing helps protect your sender reputation by reducing bounce rates, spam complaints, and other negative signals that could harm your reputation with ISPs and email service providers.

  • Cost savings: Sending emails to many inactive or invalid email addresses wastes resources such as email sending fees and marketing efforts. Regularly scrubbing your email list can save costs by targeting a more engaged and responsive audience, maximizing your email marketing campaigns' return on investment (ROI).

  • Compliance with regulations: Email scrubbing ensures compliance with anti-spam regulations such as the CAN-SPAM Act and GDPR. By removing unsubscribed or non-consenting subscribers from your list and providing a clear mechanism for recipients to opt-out of receiving emails, you demonstrate respect for recipients' preferences and legal requirements, reducing the risk of regulatory penalties and maintaining trust with your audience.

List Email Scrubbing Steps

1- Find Inactive Subscribers

The first step in email list scrubbing is to identify inactive subscribers. These individuals haven't engaged with your emails for a significant period, typically six to twelve months, indicating a lack of interest or disconnection from your content.

You can use email marketing software or analytics tools to analyze subscriber activity, such as open rates, click-through rates, and email interaction history.

This will allow you to gain insights into audience behavior and tailor your email list cleaning process to focus on those no longer actively engaging with your content.

2- Segment Inactive Subscribers

Once you've identified inactive subscribers, the next step is to segment them based on their level of inactivity and engagement history.

Segmentation allows you to categorize subscribers into distinct groups, such as those who haven't opened an email in the last three months versus those who haven't engaged in over six months.

So, segment inactive subscribers to tailor your re-engagement efforts and communication strategies to address their specific needs and preferences.

For example, you may offer targeted incentives or content based on each segment's behavior and interests to encourage re-engagement.

3- Find Duplicated and Misspelled Email Addresses

Inaccurate or duplicated email addresses can skew your marketing metrics and waste resources. As part of the email scrubbing process, it's essential to identify and remove duplicated and misspelled email addresses from your list.

Email validation tools can help identify common formatting errors, such as typos or missing characters, and detect duplicate entries.

Cleaning up these discrepancies ensures that your email list is accurate and eliminates unnecessary duplicates, improving deliverability and engagement rates.

4- Re-Engage Inactive Subscribers

Re-engaging inactive subscribers is a proactive strategy to revive interest and reconnect with individuals who have previously disengaged from your emails.

This step involves sending targeted re-engagement campaigns or win-back emails to encourage inactive subscribers to re-engage with your content.

Re-engagement emails may include special offers, personalized recommendations, or surveys to gather feedback and understand why subscribers stopped engaging. You can reignite their interest, strengthen relationships, and convert them into active and engaged subscribers.

5- Remove Inactive Subscribers

After attempting to re-engage inactive subscribers, the final step in email list scrubbing is to remove those who remain unresponsive. Continuing to send emails to inactive subscribers wastes resources and can harm your sender reputation and deliverability rates.

Regularly removing inactive subscribers from your list ensures that your email marketing efforts focus on engaging with a genuinely interested audience and being responsive to your content.

This helps improve email deliverability, engagement metrics, and campaign effectiveness while maintaining a clean and healthy email list.

Best Email Scrubbing Tools


NeverBounce offers real-time email verification and list cleaning services to help reduce bounce rates and improve email deliverability.

When you run your email list through NeverBounce’s email verifier, you can quickly identify the following types of emails: valid and invalid emails, disposable, catch-alls, and spam traps.

It will also tag accept-all emails and unknown results as either “SAFE” or “NOT SAFE” to send based on your email list health and current email service provider (ESP).

NeverBounce declares to its customers that it can provide 99% successful email deliverability. You can receive your money back if you continue to bounce emails with a higher than 3% bounce rate.

You can try it for free. Prices start at $0.008 per email, up to 10,000 emails.


Mailbite is a powerful tool for email verification, email verification service, email validation, bulk email list cleaning, email list validation, email checker, verifying email address, email cleaning, verifying email list, and bulk email verifier.

It works online in a browser, no installation required. Pricing starts at $19,90 for 25.000 Email Verifications


With EmailListVerify, users can quickly clean their lists, removing invalid and dangerous email addresses to improve campaign performance.

This automated, self-service web application lets users validate their email lists quickly and securely.

EmailListVerify reduces bounce rates and improves email marketing campaign ROI’s for businesses and marketers by:

  • Cleaning email lists by detecting invalid or non-operational mailboxes.
  • Ensuring no email on the list receives an unsolicited message during validation.
  • Handling data securely with the industry's highest level of data encryption.

Their pricing starts at $0.0003 per email, for 10,000,000 emails.


ZeroBounce email verification plugin assists users by validating email addresses entered into registration forms, comments sections, eCommerce shops, and more.

It works by installing the plugin, connecting the API key, and selecting the forms to monitor with email validation.

ZeroBounce counts with automated real-time email validation detect more than 30+ email address types, fast manual email validation, and email validation API logs to keep track of monthly email verifications, including status, sub-status, IP, date, and credits used.

Pricing starts at $18 per month, for 2,000 emails.


Regular email list scrubbing is a non-negotiable practice for marketers aiming for effective email marketing campaigns.

Maintaining a clean list ensures that your messages reach genuinely interested subscribers, leading to higher engagement, better deliverability, and ultimately, more conversions.

With the right tools and practices, email list scrubbing can significantly impact your marketing efforts' success.
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