Automated List Hygiene That Runs Without You

Most eCommerce brands know they should clean their lists. Almost none of them actually do it consistently.

The reason is simple: it's tedious. You have to decide who to suppress, create the segment, convert it to a list, do the suppression, and hope you didn't accidentally remove someone who was about to buy. So it gets pushed off. Then pushed off again. Then the list bloats, your Klaviyo bill grows, deliverability drops, and you're sending to people who will never open another email.

We built a system that handles all of this automatically with no manual exports, no decisions to make, and no forgetting to do it. Once it's set up, it runs in the background forever.

I've never seen another agency do this. Most are still doing manual cleanups once a quarter—if they remember.

The Problem With Manual List Cleaning

Here's what usually happens:

Someone on your team notices engagement rates are dropping. They pull a segment of unengaged profiles. They look through it. They suppress the profiles manually. Then they move on and don't think about it for another 3-6 months.

In the meantime:

• New dead weight accumulates daily
• You're paying for profiles that will never convert
• ISPs see your engagement rates drop and start filtering you to spam
• The profiles you should have removed are dragging down your deliverability for the profiles who actually want to hear from you

The manual approach doesn't work because it relies on someone remembering to do it, having time to do it, and doing it consistently. That's three points of failure.

The Automated Sunset Flow

Here's the system we built. It runs continuously across most of our clients with zero ongoing maintenance. If you're new to Klaviyo flows, check out our guide on what Klaviyo does and how it drives email marketing success.

Step 1: The Trigger Segment

We created a segment that captures truly dead profiles. Use our Audience Builder tool to quickly create targeted segments like this. Someone enters this segment when ALL of the following are true:

• On the list for longer than 270 days
• Has not opened an email in the last 270 days
• Has not clicked an email in the last 270 days
• Has not visited the site in the last 270 days
• Has not made a purchase (ever)

This isn't "hasn't opened in 60 days"—that's too aggressive. At 270 days with zero engagement across every metric, these people are gone. They're not coming back.

When someone meets all these criteria, they enter the segment. That segment entry triggers a flow.

Step 2: One Last Email

The first step in the flow is a single re-engagement email. It's dead simple—100% plain text, no design, no images. It reads like an actual email from a person:

That's it. No discount. No desperate plea. Just a straightforward "we're going to stop emailing you unless you tell us otherwise."

If they open, click, visit the site, or do anything that shows engagement after receiving this email, they exit the flow. They're back in the active audience. The system caught them.

Step 3: The 10-Day Wait

The flow waits 10 days to see if they engage.

Why 10 days? It gives Klaviyo time to register any engagement. Email opens don't always track instantly. Someone might open it on day 3 but the data doesn't sync until day 5. The delay is a buffer to make sure we're not suppressing someone who actually engaged.

Step 4: Backup List

Before suppression, the flow adds them to a static list. Think of it as version control.

This exists for a few reasons:

• If something goes wrong, we have a record of who was suppressed
• Clients can review who was removed if they want to
• If there's ever a question—"did we suppress this person?"—we can check
• It gives clients a sense of control and safety

It's a simple safety net that takes one extra step to set up and saves potential headaches later.

Step 5: Webhook to API for Suppression

Here's where it gets interesting.

Most people would stop at "add to a suppression list" and suppress manually. I've seen it a million times—a custom property with "Sunset". Which then has to be done later... We use a webhook that calls Klaviyo's API directly.

The webhook sends the profile to the API with a suppression command. The profile gets fully suppressed—not just removed from a list, but suppressed at the account level so they won't receive any marketing emails.

This is the part I've never seen anyone else automate. The webhook-to-API connection means the entire flow is truly hands-off. No human touches it. No exports. No manual suppression steps.

The Results

We've cleaned up 30,000-40,000 profiles across clients since implementing this.

That's 30-40k profiles that were:

• Costing money to store
• Dragging down engagement metrics
• Hurting deliverability
• Never going to buy anything

They're gone now. And every day, the system catches more. Plus, this isn't a system that someone has to maintain. No "well when we leave—the agency—here's a 47-item checklist of things you have to do to keep the system running."

We don't have long-term deliverability data yet since this is relatively new, but the math is simple: removing dead weight improves the ratio of engaged to unengaged profiles, which improves engagement rates, which improves how ISPs view your sending reputation. For more on the business impact, check out our Klaviyo Bill Reducer tool to see how much you could save.

Why This Matters

List hygiene isn't complicated in theory. Everyone knows they should do it. The problem is that manual processes don't get done consistently.

The unlock here isn't some brilliant insight about email marketing. It's just automation applied to something everyone knows they should do but doesn't.

Build it once. Let it run. Stop thinking about it.

That's 30-40k fewer dead profiles, and I haven't thought about list cleaning in months.

If you run an email program and want to see how this could work for your setup, reach out. Check out how we helped Bussin Snacks achieve 49% owned revenue or Jambo Superfoods grow 7X email revenue through automated Klaviyo strategies like this.