To delete an entry, scroll to the entry, and press the overflow menu (3 dots on top-right corner). Press “Edit”. In the editor mode, press “delete”.
Warning! Deleted entries cannot be retrieved.
Clearing hidden in-app data:
To remove hidden in-app data, you have to do it from Google Drive. Go to http://drive.google.com. Press “Settings” (Gear icon), and select “Manage apps”. Scroll to “Journey” and click on the “Options” button. Lastly, click on “Delete hidden app data”.