How and why you should cleanse your email database

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Cleansing the database is not something that gets people up in the morning, but leaving it too long will cause your more pain. Read on for why you need to cleanse your email database now and how to go about it.

How and Why you should cleanse your database.


If you have a dirty database with invalid addresses or out-of-date subscriptions, it will lead to inbox placement issues in the future. Internet Services Providers look at how many spam traps, complaints and bad addresses you are sending to as their prime means of assessing your sending reputation, the factor behind good deliverability.


Sending to inactive customers who have not opened an email in the last year will be costing you money. Yes, email is relatively inexpensive, but those ESP transmission costs all add up. First you need to prove that it’s OK not to send to inactive customers. Keep back half from your next send, and see how many of those purchase compared to those who get the email. Keep in mind that just because they don’t open the email doesn’t mean they are not influenced by it landing in their inbox.


Your ESP will de-dupe email addresses but are you looking for the same customer appearing with multiple email addresses? This will require you to combine other customer data such as postal addresses but failing to do so might mean you are sending re-activation emails to customers who are simply making sales through a different email address.

Removing Spam complaints, unsubscribes and invalid addresses

Your ESP plays a key role in ensuring this happens without any effort on your part. All major ESP’s, like Emailcenter, will operate a ‘feedback loop’ with top email providers including Yahoo and Hotmail which send any complaints to the ESP and they will flag these in your list so they don’t get sent to again.

Unsubscribes work in many different ways and the important consideration is to find an ESP who don’t just unsubscribe someone from a particular list, otherwise, if you load data into a new list you may end up sending to unsubscribers again.

With regards to bounces, we would recommend that you always take them with you when you move ESP. At Emailcenter, we automatically add your bounce lists on to your master suppression list, eliminating the chance of you sending to previously bounced addresses.  

Filter at the point of sign-up

One method to cleaning data is to do it in real-time at the point the customer enters their information. Real-time verification services will check to see if an email address actually exists at the point it is entered by the customer.

About Rupert Adam

Marketing Manager at Emailcenter, the UK's largest independent ESP.