Deleting Inventory Items and a feed
Make sure you are on the Account that you wish to remove the inventory feed items and feed from.
Click Settings
Scroll down to the Apps and Data Sources section.
Find the data feed that you wish to remove and click Settings
Scroll all the way to the bottom and click Delete all items created from this feed
Click Delete
Wait for the green popup saying "All inventory attached to this feed was successfully deleted"
Click Delete Feed
Click Delete
Now you can safely click Remove to remove the app from your account as well.
Click Remove
Your feed and all inventory items in it have now been removed.