Scrub Smarter, Not Harder
Why Email List Hygiene Needs an Update in 2025
Today’s email analytics don’t capture all engagement data—not even close. Nearly a third of your subscribers could be opening and reading your emails without ever triggering an “open” in your reports, thanks to ad blockers, privacy protections, disabled image settings, and other tracking limitations.
When you scrub your list based only on “opens,” you risk removing subscribers who are actually engaged but invisible to your tracking system.
🛠️ How Email Open Tracking Really Works
Open tracking is powered by a small invisible image (usually 1x1 pixel) embedded in an email’s HTML. When a recipient opens the email, their email client loads the image from a server — and that triggers an “open” event.
Simple in theory. Increasingly complicated in reality.
🔎 5 Major Factors That Distort Open Rate Tracking
Ad Blockers and Privacy Tools
Many ad blockers block tracking pixels entirely — preventing opens from being registered.
Image Auto-Loading Settings
Some users or email clients block images by default, meaning the tracking pixel never loads.
Proxy and Preload Behavior
Apple’s Mail Privacy Protection (MPP) preloads email content through proxy servers, often creating false opens or obscuring real ones.
Corporate Firewalls and Security Tools
Enterprise IT environments can strip tracking pixels or prevent external image loads.
Plain Text Email Formats
Recipients who view emails in plain text will never trigger a pixel — because there’s no HTML to load it.
📈 The Reality You Can’t Ignore
Approximately 32% of U.S. internet users have ad blockers enabled.
Privacy trends are accelerating. Laws, settings, and tech changes will only make tracking less reliable over time.
✅ Updated Best Practices for Scrubbing Email Lists
View open rates as directional, not definitive.
Prioritize clicks over opens. Click tracking remains largely reliable across devices and privacy settings.
Only remove addresses that have no opens AND no clicks within at least a 3 to 6-month window.
Send a Re-Engagement Email before scrubbing:
Subject Line: “Still Interested?”
Call-to-Action: “Click here to stay subscribed!”
Even a single click is proof of ongoing interest.
🧠 Final Thought: Scrub Smarter, Not Harder
The goal isn’t to maintain the biggest list. The goal is to maintain the most engaged, healthy list possible — without mistakenly deleting your silent champions.
Today’s smartest marketers build strategies that assume some engagement is happening behind the scenes, even when pixels can’t see it.
🔄 Beyond Scrubbing: Smarter Strategies to Re-Engage Before You Remove
If you’re concerned about scrubbing away good potential customers, you’re not limited to just re-engagement emails.
You can get even more strategic by integrating email addresses into paid media campaigns before making final decisions.
🎯 Use Retargeting to Re-Engage Cold Subscribers
How?
Upload your list of inactive subscribers into Facebook (Meta), LinkedIn, or Google Ads as a Custom Audience.
Run a targeted re-engagement ad campaign just for them.
Focus messaging on:
Reminding them of your value
Offering a special incentive (free download, discount, webinar)
Asking them to update their preferences or resubscribe
Result:
You create another channel for re-engagement, hitting people who might have missed your emails but are still interested in your brand.
Even a single click on a retargeting ad could justify keeping them on your email list — or at least moving them into a lower-frequency “cold but valuable” segment.
