We'd advise against this kind of 'manual' intervention on your part in regards to ad locations and deleting / disabling them.
The system is constantly testing different ad locations, sizes, combinations, etc. and deciding which are helping UX and rev and showing them more consistently, and which are not generating better rev / UX and not showing them as frequently.
There's really no need to do anything manually as you're suggesting, and it can actually significantly hurt potential revenue to remove them from testing.