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Bounced emails are the bane of every marketer. When an email address goes bad, it causes damage to our marketing efforts in several ways.

Bad Rep

A bounced email address is one of the signals that email deliverability services use to indicate we might be spammers. The more bounced email addresses we have on our list, the more likely we’ll raise red flags.

Broken Ads

If we use our email list as a custom audience for retargeting/remarketing, then the more bad email addresses we have on our list, the smaller our reach becomes.

The Cleaning Problem

The toughest part of fixing bad emails is the way they’re reported. They come in a pile to our inbox which often looks like this:

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That sure isn’t helpful. To clean our lists, marketers have resorted to forcing interns to read through bounced messages and keep a running spreadsheet of bad addresses. As one might imagine, this means that email list updates and bounce removals don’t happen very often.

The Cleaning Solution

I struggled with this problem with my own mailing list. How do I keep my list clean? When we look at the message above, it’s clear that simply extracting all the emails isn’t the way to go; different bounce codes mean different things. A “mailbox full” error message isn’t a reason to unsubscribe someone from my list. The answer must be to remove programmatically, based on context.

Thankfully, the power of the UNIX utility grep, which is available on Linux, Mac OS X, and Windows 10, helps solve this problem. By exporting all my email bounces into one gigantic log file, I can parse the log file to identify error messages which clearly indicate the email address has gone bad. Once done, it’s a simple matter to extract the email addresses and flag them in my marketing automation software as unsubscribe/do not contact.

Try It Out

My script is available for free on Github under the GNU Public License.

I encourage you to grab a copy and use it for your own email marketing efforts!


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