Email list clean up

To explain email list clean up, we should see it from a spam filter perspective. Imagine being the one in charge of filtering emails. You decide whether an email lands in the spam folder, or the inbox. During your shift, you were looking at the sending history of a domain, and you notice that this sender is sending to invalid email addresses. How would you perceive this sender?

The immediate idea you might get is that this sender doesn't know the people they're contacting. Think about it, if you send an email to an incorrect address aiming to contact a friend, you will try to correct it, or ask them to double check their inbox, and make sure your communication is received properly.

But, you definitely wouldn't send emails to this address every day without correcting it. If you do, that's suspicious!

This is exactly what spam filters do whenever an email is sent. They look at your history, and see if you're sending emails to people you know. Otherwise, they can mark your emails as spam.

Solution? You need to clean your email list. In this article, I'll explain to you briefly what it means, and how a clean email list can drastically improve your deliverability.

How do you know that an email is invalid?

Identifying invalid email addresses is quite straightforward. If something goes wrong with the sending, email providers usually would usually respond with a notification about the status of the error. In the email marketing terms, this email notification is called a bounce.

To detect invalid emails, you can check these bounce notifications in your inbox. Based on the type of the bounce, you can decide on what to do to have a clean list. There are mainly two types of bounces: soft bounces, and hard bounces.

Soft bounces

A soft bounce is an email notifying you about a temporary error that prevented your recipient from receiving your email. It means that their server might have had some issues when you tried to send them an email. Here's an example of a soft bounce notification:

Generally, these issues are temporary, and you don't need to worry about them. You couldn't have done anything differently to avoid such issues. Email providers would try to send multiple times, before giving up. And some providers would give you the option to configure the number of tries manually.

What you can do if you encounter a soft bounce is checking if it's frequent. A high frequency of soft bounces from the same email address could indicate that the issue might not be in fact temporary. In that case, you'd better remove that address from your email list.

Hard bounces

A hard bounce is an email notifying you about an permanent error that prevented your email from reaching your recipient. This is a more serious notification when it comes to email deliverability. You should try avoiding it at all costs.

A hard bounce could be caused by sending an email to an incorrect email address, or outright nonexistent. In both ways, it's bad new for your sender reputation.

If you receive a high number of hard bounces, this can indicate that you're sending emails to people you don't know, and spam filters don't like that for multiple reasons. As, if you were to send an email to a friend, or someone in your contact list, their email won't be incorrect, or nonexistent. We explain this further in our article on how spam filters work.

The solution is simple: remove invalid addresses from your list. Whenever you receive a hard bounce email, you should immediately remove the email address from your list or correct the spelling on it if you know the right one. It makes sense too, as you won't reach that person anyways, so no need to keep the email in your list. Here's an example of a hard bounce email:

Don't get me wrong though! Yes, hard bounces are dangerous, but one hard bounce is not harmful. You can easily write an email address incorrectly while sending an email to a friend, and you shouldn't be penalized for a small mistake. At the same time, you shouldn't have multiple bounces in a short period of time. That's when your email activity becomes suspicious. So, how many bounces are too many bounces?

Bounce rate

If you're using an emailing tool, one of the metrics that it can be tracking is bounce rate.

Bounce rate is the number of bounces you got out of a hundred emails sent. Tools track this rate so that you don't have to keep tracking bounces manually.

There is no fixed number as to how many bounces are too many bounces, but generally a 2% bounce rate is considered too high. I was hesitant to give this number, as it might suggest that upon seeing a bounce rate below this threshold, you might think that it's fine and move on. But, in reality, the best way to proceed is removing all the bad email addresses from your list. I'll talk more about this in the next section.

All what I mentioned up until now are methods to catch the bounce issue after it happens. Sometimes, this method works out, especially if your contact list is new, and was carefully collected. You send your campaign, and the bounce rate is low.

But, what if your list is old, and you haven't contacted them for a while. You can't afford to risk your domain reputation by contacting the list without verifying it beforehand. This is where email verification tools come into play.

Email verification tools (prevention)

Email verification tools are tools that enable you to verify if an email address is valid or not. When you verify a list with one of them, you can prevent bounces before even sending and thus avoid running into deliverability issues.

They have their ways of checking the validity of the email. But, they're not 100% always accurate. But still, they're a good way to prevent risking your whole emailing setup.

I highly recommend checking your list in one of these email verification services. There are a lot of them out there like: Clearout, Neverbounce, hunter, Emailable...

Now that we covered bounces, are there any other ways to optimize my list for better email deliverability? Yes, it's subject of the next section.

Optimizing your campaigns using advanced email list clean up methods

The hidden issue with an unclean email list is its impact on your engagement. Email campaigns are like social media posts, they generate their type of engagement measured by engagement metrics: open rates, reply rates, click through rates...

Sending to an invalid email address is just a waste of a send. And the send is taken into account in your engagement metric, making them lower. In the same vein, you can use a different cleaning method to maximize your open rates, and improve your deliverability consequently.

Remove the people who don't open/interact with your emails

If someone doesn't open your messages repeatedly, it means they're not interested in them. Might as well stop sending to them, no? You might feel some fear of missing out, maybe they would some day open the message and it would be all worth it. However, it's not effective as you're taking two big risks:

First, spam filters love looking at your engagement metrics, including open rates. It's on of the ways they can evaluate your deliverability. If your open rates are low, you might start landing in spam. And that's the first risk of keeping contacts who don't open your messages.

The second risk is the contacts themselves. Think about it, if you receive several messages from the same person, and you avoided opening them repeatedly, wouldn't it mean that they might grow annoyed? In this case, they might mark you as spam, which is one of the most harmful actions to your deliverability.

Speaking of which, there's another thing that I should mention, and would help your deliverability

Unsubscribe button

You should add a way for your recipients to stop receiving messages from you. Otherwise, you could risk them reporting you as spam to stop receiving them. The thing is spam complaints could stop you from reaching other recipients, so you'd better avoid them altogether.

Hopefully, there is an option of adding an unsubscribe button to your emails. Adding it would help you avoid some spam complaints, as well as have a clean list. Don't forget to remove the email addresses of people who unsubscribed!

Is there any preventive measure besides tools?

Double Opt-in

If you're collecting email addresses from your list using some kind of lead magnet, you can implement a double opt-in method. It's basically asking your new leads to confirm their email address from their inbox. This way, you can make sure that you collect valid email addresses from the get-go, and you can avoid using email verification services.

To sum up, a clean email list is an important parameter for improving your email deliverability and optimizing your marketing efforts. If I had to say it briefly, you should aim to maximize the engagement from your recipients at all costs. And a clean list would help you reach that.