Define inactive in one sentence
Write the rule down before you touch the list. A good starting point is: "No click, reply, form submission or website visit in the last 90 days, and they joined more than 90 days ago." Adjust the number to your sending frequency. If you email weekly, 90 days is generous. If you send once a month, use 180.
Use clicks and replies, not opens. Privacy features in some mail apps open emails automatically, so an open count flatters you and can hide people who never read a word.
Build a list of the people who match
In your email tool, create a segment using the rule. Tools such as HubSpot, Mailchimp, ActiveCampaign and Brevo all let you filter on last engagement. Save the segment so you can use it again next quarter.
Check the size. If it is under 10 per cent of your list, your list is in decent health. If it is 40 per cent, you have a bigger problem and you should look at how people join, not only at who to remove.
Take out the people you must keep
Before you act, subtract anyone who should never be removed by a rule:
- Current customers, even if they ignore marketing email.
- Anyone with an open deal or an upcoming meeting.
- Anyone who replied to a human email recently.
- Partners, investors and other people you know personally.
Create a "protected" property or tag in your CRM and exclude it from the segment. Doing this once saves you from deleting the wrong person later.
Send one re-engagement round first
Give inactive people one fair chance to stay, with a short sequence of two or three emails over two weeks. The detailed approach is in Re-engagement. In short: a clear subject line, an honest "Do you still want to hear from us?" and one button that confirms they do.
Do not try a clever offer to bring them back. If a discount is the only reason they reply, they are not the audience you built the list for.
Remove, but do not delete everything
Contacts who do not respond to the round should stop receiving marketing email. In most tools you can mark them as unsubscribed or move them to a non-marketing status. That is better than deleting them, for two reasons. You keep the history of the relationship, and you keep a record that stops them being re-imported later by accident.
Delete only what you have to. If someone asks you to erase their data, do that fully and follow your privacy rules.
Clean up the addresses that bounce
Hard bounces are addresses that do not exist. Remove them straight away, without waiting for the next prune. Keep your bounce rate under 2 per cent and your spam complaints well under 0.1 per cent. If your tool shows more, fix the list before you send another campaign.
Make it a habit
Put it on the calendar. Prune once a quarter. Each time, write down the list size before and after, the number removed and the open and click rates of the next three sends. After two or three rounds you will know what is normal for your audience.
Common mistakes
- Using open rate as the only measure of activity.
- Removing customers because they ignore marketing email.
- Deleting contacts so that they come back again from the next form import.
- Pruning once, then never again.
- Skipping the re-engagement round, so people who would have stayed are lost.
How you know it works
Your click rate goes up because the same clicks are divided by fewer people. Bounces and complaints fall, and campaigns land in the main inbox more often. Check this against your numbers from Review open and click rates monthly. A smaller list that gets read is worth more than a big one that is ignored.
