How to delete the ITSM Dynamic Fields after ITSM module uninstall

[bogdanmoldovan]

Initially, before going live with our OTRS installation, we also deployed the ITSM modules.
In time, as we understood more the OTRS Framework and functionalities, we came to the conclusions that we do not need ITSM. So we uninstalled the modules.
Now, as we begin to be more and more fluent with OTRS and creating Postmaster filters, follower by Generic Agent Rules, Event Notifications, custom states and own Dynamic Fields, I wanted to perform a little clean-up and saw that I still have the ITSM related Dynamic Fields but I cannot delete them.
I have even attempted to update the dynamic_field table with 0 on the column internal_field and checked to see if the delete icon appears in the Admin / Dynamic Field section in order to delete a certain dynamic field (ITSMImpact for example).

So, my question is, how can I delete the ITSM related dynamic fields after the ITSM uninstall?

Thanks in advance