How to Clean Your List and Remove Inactive Subscribers

A large contact list feels like an asset — but a list full of people who never open your emails is actually a liability. Inactive contacts drag down your engagement rates, damage your sender reputation, and inflate your costs. Regular list cleaning is one of the most important maintenance habits in email marketing. This guide explains when to clean, who to target, and how to do it safely.

Why List Cleaning Matters

Inbox providers pay close attention to how recipients respond to your emails. When a large proportion of your list consistently ignores your campaigns — no opens, no clicks — it signals that your emails are not welcome. Over time, this contributes to:

• Declining inbox placement rates as providers begin routing your emails to spam

• Lower open and click benchmarks that make your campaigns appear to perform poorly

• Higher bounce rates if inactive addresses have since become invalid

• Inflated contact counts that do not reflect your true, reachable audience

What Counts as an Inactive Subscriber?

The most common definition of an inactive subscriber is someone who has not opened or clicked any of your emails over a defined period. Most email marketers use one of the following thresholds:

• 90 days – Suitable for brands that send frequently (multiple times per week)

• 6 months – The standard threshold for most email programmes

• 12 months – Appropriate for brands that send infrequently or run seasonal campaigns

Choose the threshold that makes sense for your sending frequency. A contact who has not opened in 6 months but you only send monthly is very different from one who has not opened in 6 months of weekly campaigns.

Step 1: Identify Inactive Contacts in Mailzzy

1. Go to Contacts.
2. Use the filter options to locate contacts who have not engaged within your chosen time window. Filter by last open date, last click date, or campaign interaction history.
3. Review the filtered list. Before taking any action, tag these contacts with a label such as “Inactive Review – [Date]” so you can track them through the cleaning process.

Step 2: Run a Re-Engagement Campaign First

Before removing inactive contacts permanently, give them one final opportunity to re-engage. A short re-engagement campaign — one or two emails with a compelling subject line and a clear call to action — can recover a meaningful percentage of these contacts.

Wait for the re-engagement campaign to complete and note which contacts responded. Those who open or click should be removed from your inactive tag and returned to your normal sending rotation.

Step 3: Remove Non-Responders

Contacts who did not engage with your re-engagement campaign can now be removed from your active list. Depending on your preference:

• Unsubscribe them – Their record remains in Mailzzy but they receive no future campaigns. Their opt-out history is preserved, which protects you if questions arise later.

• Delete them – The record is permanently removed. Use this only for addresses you are confident are invalid or genuinely unwanted. Deleting removes the opt-out history.

To take action in bulk, select the inactive contacts in Mailzzy, open the bulk actions menu, and choose Unsubscribe or Delete as appropriate.

Step 4: Remove Hard Bounced Addresses

Hard bounces — addresses that permanently failed to deliver because they no longer exist — should always be removed after every campaign. Mailzzy automatically suppresses hard-bounced addresses from future sends, but reviewing and deleting them from your account keeps your contact count accurate and your list hygiene clean.

How Often Should You Clean?

At minimum, run a full list clean every 6 months. For high-volume senders, quarterly cleaning is better. After any large import from a new data source, review the list for bounces and inactivity before sending a campaign to the entire combined audience.