List hygiene is one of the most reliable ways to improve email deliverability. A smaller, cleaner list that engages well outperforms a large list full of inactive contacts every time — in open rates, click rates, and inbox placement. The deliverability logic is simple: inbox providers watch engagement. When too many recipients ignore your emails, they start routing your emails away from the inbox for everyone.
Why Cleaning Matters
- Hard bounces (invalid addresses) damage sender reputation when they accumulate
- Inactive contacts that never open drag down engagement metrics
- Spam trap addresses hide in old lists and trigger blacklisting
- A smaller, engaged list is literally more valuable than a larger, disengaged one
Who to Remove
- Hard bounces: MONDAi automatically suppresses these — confirm they are suppressed and not still receiving campaigns
- Soft bounces (repeated): Three or more soft bounces in a row = effectively invalid
- Unsubscribed contacts: MONDAi automatically marks these — confirm they are not being sent to
- Chronically inactive: No email open in 6+ months with 10+ emails sent
Steps
Go to Contacts and build a Smart List of inactive contacts
Filter: last email open was more than 180 days ago AND total emails received is more than 10.
Send a re-engagement campaign to this segment first
One email. "Are you still interested in hearing from us?" Give them a reason to stay. Some will re-engage.
Wait 7 days
Anyone who opens or clicks during that window is re-engaged — tag them accordingly.
Suppress or delete contacts who did not re-engage
Add a "Suppressed — Inactive" tag and exclude them from all future campaigns.
- Deleting contacts instead of suppressing — suppression preserves the history and prevents the address from being re-imported later.
- Never running a re-engagement campaign before suppressing — you will remove people who would have responded.
- Cleaning once and considering it permanent — list hygiene is an ongoing practice, not a one-time event.
- Waiting too long to clean — clean quarterly.
Next steps
Still stuck?
- Search the MONDAi Help Center
- Email support@mondai.io with a Loom video
- Ask inside the ArchiTech Channel
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