Create a Microflow: Retrieve from database all DBDetails, resulting in a list and Delete the list.
Marco’s solution works perfectly. However I’m going to tell you another way to do it.
When the app is running on studio pro. In the bottom bar inside the console tab you have the menu “Advanced”
There you have the option to view the built-in database that mendix is using.
There you will have all the tables of the Mendix Database and you can execute some queries to see all the info within the tables and also the opportunity to remove all the records