how do I delete an application?

There are two ways to delete an application.
One way in new UX is to go to Settings, then App Management, then Delete app.

If you are the Realm Administrator, you can also go into manage your Realm and look at a List of all the apps and delete from there.

I am new to QB so I testing with pre-built QB apps. When I am done with "experimenting" and have deleted such an app. because I have completely mis-understood some relationships, I have Deleted the app BUT when I want to get it again, the version QB returns has several of the changes I made in the previously downloaded application instead of a "clean" application...is there anything I can do to "scrub" my history?