Best Practices for Email List Hygiene

Best Practices for Email List Hygiene
Valeriia Dziubenko Valeriia Dziubenko 11 june 2024, 11:00 71
For beginners

Running an email list requires regular hygiene practices. You should frequently clean up your email list to get rid of inactive and unreachable addresses. No one wants to lose active subscribers, but unengaged recipients reduce your open rates and affect your sending reputation.

If many subscribers ignore your emails, email providers may think you're sending irrelevant content, which could impact your deliverability for further emails. Email hygiene helps you avoid this issue and maintain high engagement rates. This article will explain what it’s all about and how it works.

What is email list cleaning?

Email list cleaning entails deleting inactive, invalid, and unengaged email addresses from your subscriber list. This ensures that you send emails only to people who want them and will likely engage with your content.

It might seem upsetting to purposely reduce your subscriber count, but remember that quality counts more than quantity. Having a smaller, engaged audience is better than a large but mostly disengaged one. The former gives you high conversion rates, while the latter gives low conversions, negatively impacting your sending reputation.

Why is email list hygiene so important?

Email list hygiene is important for many reasons, including:

1. Boosting your sending reputation

Sending reputation is the score that big email providers like Gmail and Yahoo Mail and special reputation services like SenderScore assign to your domain name and IP address. The higher your score, the likelier your emails will reach the intended recipients’ inboxes.

Open rates contribute significantly to your sending reputation. If you have a largely disengaged audience, your open rates will be low, damaging your sending reputation. However, email hygiene lets you mitigate this issue – you’ll comb through your subscriber list to remove inactive addresses or invalid addresses that cause bounced emails.

2. Lower marketing costs

Regular email hygiene means you’ll avoid wasting resources on recipients who hardly engage with your emails. You’ll regularly remove the addresses with little or no engagement and focus on the ones with solid engagement. This way, you’ll achieve better results with the same email marketing budget.

3. Reduced chances of hitting the spam folder

Sending messages to unengaged addresses increases the likelihood of being marked as spam. Email providers pay attention to engagement rates and consider domains with low engagement as possible spam sources.

Email hygiene involves pruning disengaged addresses from your subscriber list and focusing on the engaged ones. This way, you’ll improve your domain reputation and reduce the chances of your emails entering spam folders.

Simple steps to clean your email list

Maintaining email hygiene is a simple task. You just need to perform some crucial steps and do that frequently. The steps of implementing email hygiene include:

1. Define your cleanup frequency

The first step is determining how often you'll scrub your email list. The rule of thumb is to clean it every 3 to 6 months, but you can go much further and clean it every month or two. Larger email lists (100,000+ subscribers) need more frequent cleaning than smaller ones.

Pro tip: Do not exchange email lists or purchase them from anyone. That may seem like a viable short-term solution, but you’ll likely harm your domain reputation and struggle to get good engagement rates. At worst, you could be added to a deny list, causing your messages to go straight to spam folders.

2. Identify disengaged contacts

Email hygiene involves examining your email list to identify addresses not engaging with your messages. These addresses can be legitimate addresses that don't open your messages for whatever reason or invalid addresses that don't receive your messages at all.

It’s difficult to accurately identify invalid addresses all by yourself. However, your email service provider (ESP) likely has an analytics dashboard that shows the unreachable addresses, as well as open and conversion rates for each address. If your ESP offers callback notifications, you might prefer to write a script to automatically remove unreachable addresses and take note of low-engaging ones.

Alternatively, you can use email list hygiene services like Verifalia and EmailListVerify. You’ll upload or import your subscriber list; these email list hygiene software scan every address to determine whether it’s valid. You'll be notified about any invalid email address to easily remove it.

3. Try re-engaging inactive subscribers

You don’t have to give up on disengaged subscribers immediately. Instead, you can try to re-engage them and see if they respond. A re-engagement campaign involves sending messages reminding subscribers that you value them and want to hear back from them. You can chip in a discount or a free virtual gift to entice such customers to re-engage with your brand.

Below is a sample re-engagement email from Duolingo, a popular language-learning app. It tells the recipient that Duolingo hasn’t heard from them for a while and asks whether they will continue interacting with the app.

Source: Really Good Emails

Most experts recommend sending 3 to 4 re-engagement emails before giving up on a subscriber. Anyone who doesn’t interact with your brand after a few re-engagement emails has definitely lost interest, and further messages could be reported as spam.

4. Delete disengaged addresses

After your re-engagement campaign, it’s time to remove the addresses that remain disengaged with your brand. These addresses weigh down your engagement rates, which could affect your sending reputation. It’s wise to remove them even as it decreases your subscriber count. Don’t forget to also delete unreachable addresses from the list because they serve no purpose.

Email list hygiene best practices

Below are some tips for maintaining good email hygiene:

1. Use double opt-in

Double opt-in means anyone who subscribes to your list must confirm their subscription via email. When someone adds their address to your list using a form on your site, they’ll immediately receive an email with a link they must click to confirm the subscription. If this link isn’t opened, the address won’t be added to your email list.

Double opt-in ensures only valid email addresses get on your list, reducing the need for constant cleanups.

2. Use a corporate email address

Don’t use generic email addresses to interact with customers. Instead, use an email address attached to your custom domain. It should be something like or, and not or

A professional address makes your emails more authoritative to recipients and email providers. This helps boost conversions and reduces the chances of your messages being sent to spam.

3. Segment your subscribers

Segmentation entails separating your audience into different groups and sending more targeted emails to each group. You can segment according to many factors, such as gender, age group, hobby, occupation, engagement rate, etc.

For instance, you can separate your Gen Z, millennial, and Gen X groups and send targeted emails to each one. For Gen Z and millennials, you can use informal language this age group is familiar with, while sticking to the formal tone with Gen X subscribers.

Segmentation helps boost your conversion rates because each group gets tailored emails instead of generic ones they might find difficult to relate to. It leads to more engagement from your subscribers and keeps your email list healthy.

4. Avoid spam filters

Every email provider has spam filters that scan incoming emails for features resembling spam. It’s wise to understand these spam features so that you can avoid them. They include:

  • ALL CAPS subject lines: Spammers often write their subject lines all in capital letters to attract attention, so avoid this.
  • Requesting sensitive information: Never request sensitive information from your customers over email because it’s insecure and will likely be considered phishing.
  • Exclamation marks: Spammers often use exclamation marks in subject lines to grab attention. Email providers flag this behavior, so avoid it.
  • No unsubscribe link: Any marketing email without an unsubscribe link is considered spam. Hence, all your emails should include a link recipients can click to opt out of further messages.
  • Trigger words: Some words or phrases are generally associated with spam, such as "free," "no hidden fees," "no strings attached," "bonus," "money back," "this isn't a scam," etc. Using these words in the subject line or email body increases the likelihood of your messages being marked as spam, so avoid them.

5. Use a reputable email service provider (ESP)

Above all considerations, choose a reputable email service provider (ESP) with no history of shady or negligent practices. No matter how well-maintained your email list is, your efforts are futile if you use an ESP with a tainted reputation.

Email services like Gmail and Yahoo Mail can block all messages originating from a specific ill-behaving ESP, and you don’t want to encounter such issus. Look for a trustworthy ESP so that you don’t have to worry about your emails not getting delivered. Luckily, you have that in UniOne, a secure, cost-effective, and user-friendly ESP that offers high deliverability and extensive analytics. Our platform makes it easy to manage and clean your subscriber lists with dedicated tools. You can order a dedicated IP address to gain complete control over your sending reputation and maintain stellar email hygiene.


Regular cleanup is non-negotiable for brands that interact with customers via email. Email hygiene improves your engagement and deliverability rates, which leads to higher sales in the long run. We’ve explained what you need to know about email hygiene, including its value and best practices. Follow our tips to keep your email list clean and get better marketing results.

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