Yes, I figured it out. Somehow, I was not able to delete the item after using ""Get Next Item"", but that's probably because the item is locked. However, I'm able to delete the items by marking the item as completed first.
Prior to adding to the queue, I delete every items on the queue. When ""Getting Next Item"", I then see if a certain condition is met. If not, I mark it as complete, then I delete it.