(IMPORTANT NOTE: This article focuses on the specific practice of email list cleaning, not on repairing IP or domain reputation. If you think you have issues in those areas address them seperately and before you attempt any list cleaning activity).
Hold onto your hats, folks, because we're about to stir up some controversy about list cleaning.
You shouldn't be cleaning your list on a regular basis. If you are, or paying someone to do it for you, you're probably doing more harm than good.
"But wait," I hear you say, "I've been told that list cleaning is the key to a healthy list and high deliverability!!!"
Let's dive in, shall we?
Marketers Ruin Everything
For as long as time itself, email marketers have been preaching the gospel of list cleaning to their clients, swearing it's the holy grail for maintaining a healthy list and high deliverability.
At first glance, this advice seems solid.
Who wouldn't want to be look healthy and slim in the eyes of the email gods?
So, marketers jumped on this bandwagon, crafting intricate sun setting automations or mass unsubscribing users based on rules like "if they didn't click in 30 days, unsubscribe them!" or "if they haven't opened in 90 days, they're out!"
We think all this is busy work, and if done on the regular, it's probably doing more harm (to revenue) than good to your business.
Here at Bento, we've seen customers attempt to clean their lists themselves, following advice they've often picked up from Twitter or a Facebook group, but sadly, we've also seen their revenue, the main business metric, take a nosedive after they finished implementing that same advice.
Why does this happen?
Shouldn't your revenue skyrocket after cleaning your list?
Should I be hitting more inboxes and making more money?
Unfortunately not; during these cleaning sprees, legit users and leads often get unsubscribed in the process. If you're someone who has at some point scrubbed 20% or more of your list, there's a high chance you've axed a significant chunk of future revenue and earnings.
Tracking is a Mess
The main reason regular routine list cleaning based on subscriber activity doesn't work is that email metrics are broken.
Email marketing tracking has been a hot mess for a long time. Whether it's due to privacy regulations, email clients blocking tracking pixels, or users disabling tracking, the data you're using to make decisions about your list is often wrong.
Especially if you cater to a technical audience, or B2B, you'll find that many of your users are dodging tracking like Neo dodges bullets, meaning they won't be counted as "active" in your tracking system.
In addition to real users not triggering activity metrics like opens or clicks, bot users can automatically trigger those metrics too leading to you potentially purging real users and keeping the bots.
There's a different method we recommend called event-based cleaning.
Event-based cleaning focuses on specific, negative events happening to your business that could be impacting your deliverability with specific providers.
You start this type of cleaning activity when and if you've gone from a steady double digit open rate to a single digit open rate AND first ruled out that your IP address/content/domain isn't the issue (important: verify this before doing any list cleaning).
You do not clean your list if you're only seeing only a slight decrease in open rate, as it's more likely that people are just bored, not "unhealthy" — and you should keep them on your list whilst you focus on other things like improving your content or product.
We can't put enough emphasis on the fact that deliverability issues are often SHARP, SUDDEN, and OBVIOUS; they always have a root cause and you need to solve that specifically.
Here are some examples of events that could be causing issues and need to be addressed:
Event: Increased Bot Sign-ups — This is a common issue; often, forms on the web are used to gather subscribers but they are misused by spammers. If these forms aren't secured, bad actors can scrape them, add them to an attack list, and submit fake emails at mass. Why? Google "listbombing" to learn more about this shady activity.
Solution (Security) — Implement rate limiting on your forms by IP address, block all bot activity to that form endpoint, and use tools like Cloudflare's Managed Challenges at certain endpoints where bot activity could be high (e.g., account sign-up pages).
Event: Start Emailing After Years of Inactivity — We often see accounts with subscriber lists that haven't been marketed to in years run into issues.
Solution — Identify which accounts are real + recently engaged with your business (perhaps through recent sign-in activity in your database, not opens or clicks). You could gradually start emailing those users first, and archive or unsubscribe the older ones.
Event: Past Misconduct — You scraped the web for emails, like you used to do in Facebook Groups.
Solution — Just delete them.
Event: Bad Targeting — Your marketer has been running ads to the wrong audience, and now you have a bunch of people on your list who aren't interested in your product.
Solution — You could try to re-engage them, but it's probably best to just delete them and telling your ads guy/gal off for not picking this up sooner.
You'll notice that once the above solutions are implemented, the issues are resolved.
It shouldn't be something you need to do regularly. You've stopped your forms from being spammed, removed the scraped emails you added years ago, and deleted the users who haven't heard from you in a decade.
Your open rates should return to normal after a little bit of time, and you can continue to grow your list without fear of being blacklisted or having your emails marked as spam.
What Metrics to Track
There's really only one metric to track: Google's Postmaster Tools' "Spam Rate".
Keep this under 0.1% and you're golden. Anything below 0.3% is acceptable.
If you're above 1%, an "event" usually has happened and you need to investigate further.
(👆 This is a screenshot from a friend who had a spammer abusing a form of his to send bad emails, this caused all his other emails to not be delivered. We helped him identify that security issue and after he patched it he was OK).
Other metrics like domain reputation, open rate, and click rate are all secondary to this in terms of list cleaning efforts.
When Not To Clean
If nothing out of the ordinary has happened and your "Spam Rate" is below 0.3%, then you probably don't need to clean your list.
Keep marketing as usual and focus on creating compelling content for your users.
If you're finding that emails aren't being delivered, to specific inboxes, you're better off playing detective and investigating the cause of that specific issue rather than cleaning your list. More likely than not it will be an IP reputation issue, rather than a list health issue. Work with your ESP to resolve this.
Example: if your emails aren't being delivered to iCloud it's more likely that your IP is on a blacklist like Proofpoint, or you're sending emails that are being marked as spam.
It's so easy for us to create work for ourselves just for the sake of it. It's also so easy to read something on Twitter and think "I should do that too!"
However, if you study your users and subscribers carefully, you'll often find that people make purchases YEARS after signing up. Users are usually happy to receive emails until they are ready to buy. This is true in almost every info or software business we've encountered.
For Bento, we have users who have been on our list for 3 years and have only just started using our product after getting an email from us. That's normal!
In addition, compounding effect of growing a large list is real. You don't want to cut that down unless you really have to.
In addition, the marginal cost of keeping an email on a low-activity list and only sending major updates and announcements every now and again is peanuts.
If you're selling a commodity product or a $5/month newsletter subscription, then sure keeping inactive subscribers may not be worth it but at least work out the maths.
Anything with a Lifetime Value (LTV) in the hundreds or higher, it's a no-brainer to keep people on the list.
Run the maths!
Open rate is not a business metric; revenue is.
To maximize revenue, you need the largest possible audience while ensuring your emails continue to be delivered. List cleaning is a dangerous game and you should only play it when you have to which is when an "event" has happened.
If you're unsure if you should clean your list please join our Discord and ask!
We're happy to look at your specific account, identify problems, and work with you to fix them.