Not sure I understand the question.
Here is how I do it. With ctrl key depressed I hover the arrow over each cookie I want deleting thereby highlighting it. When I have made all the selections I want I depress the delete key. Those that were highlighted are gone and the rest are still there.
Does this help?
I go down my list of cookies using ctrl key to get all the ones I want to delete. This fine but what am I doing wrong that I wind up with a bunch of copies toward the end of the list that I am selctively deleteing???