Things to consider when you start "Database Cleanup"


Things to consider when you start "Database Cleanup"


While you can delete bounced and unsubscribed contacts, we will need to consider the following points before proceeding further.

You may choose to delete these contacts for the following reasons:

  • You no longer need these contacts in your account.
  • You wish to keep your list clean and avoid any potential GDPR violations with contacts you no longer use.

Or you may choose to keep these contacts in your account for the following reasons:

  • They might update their email address or subscription preferences with you.
  • They may have a deal and are progressing through your pipeline.
  • You are communicating with them on different channels.


Note : Once the unsubscribed lead is deleted from the instance and the lead fills in a form, they are automatically unsubscribed until they take an action to re-subscribe. Marketo keeps a table/record of "durable Unsubscribe" in the backend.

Also, We can have a smart campaign that changes the Unsubscribed field value from 'true' to 'false' if a lead submits a new form (i.e opt-in).  This will override the durable unsubscribe if a deleted lead is re-created via a form submission.


Invalid Email Address

Invalid emails stop Marketing strategy dead in its tracks. Without a valid email address, we as a marketers have zero visibility into those critical data points which allow them to create the most targeted campaigns in any channel. Additionally, the brand can’t remarket to potentially high-quality buyers.

Marketing to invalid emails wastes time, budget and resources. Removing invalid email addresses allows the sales team to focus on legitimate leads.

Email Invalid is a strong indicator that someone has left their company or they no longer use the email address they shared with us.

Consider removing these from your marketing automation system but not your CRM. In your CRM, add an indication field for “bad email address.” This should alert your sales team or sales operations manager that a new email address is needed.


Here are some of the 500 error codes : 

550-5.1.1 The email account that you tried to reach does not exist.
550 5.1.1 User Unknown
User unknown in local recipient table
undeliverable address
The email account that you tried to reach does not exist: 550 Invalid recipient
550 No Such User Here
550 5.4.1
550 #5.1.0 Address rejected
550 permanent failure
511 "User Unknown"
554 5.7.1
550 User not found
551 User not local
invalid recipients is found
550 No such user
Mailbox unavailable
No such user
Invalid recipient


Marketing Suspended

Marketing Suspended is marked to true when you (Marketers) don’t want the leads to receive further mailings (for multiple reasons) but still they will be able to receive operational emails.

You can set it back to False when you completely ready to send the emails to the leads.

Deleting the leads in “Marketing Suspended” is not recommended as Marketing suspended is your decision, not the lead's decision. This means you can decide when you want to remove this flag.



It's a best practice to not remove your blacklist since this a list of people you never want to receive your emails. A blacklist should not only be unsubscribed but should also be opt-ed out from receiving operational emails such as updates to your Terms & Conditions or a change in company contact information. However, if this list is large, review it to check for any records that should not be blacklisted but rather unsubscribed and make the change.

It’s not recommended to delete blacklisted leads to ensure we never send them our emails.


Hard Bounces

Hard bounces come back with a 5XX code, and should these off immediately. It’s wise to follow the “one hard bounce and you’re out”. Before removing any records from your instance, be sure you’ve tried every avenue to reconnect with those seemingly “lost” customers.


Not sync’d to CRM

Are there leads inside your marketing database that are not sync’d to your CRM? Check their recent activity. If they have not converted or their lead score has not changed in the past year perhaps you should consider removing them.



Hoping this article helps in considering what leads to delete and what leads not to be deleted and when. Please do let me know if you have any points or recommendations so that I can add and update the article for us.


Thank you.