Ack! Augeas was right, and the solution was obvious. He said:
You can of course delete cookies in the list by ticking the Cookies box in Cleaner/Windows/Internet Explorer and/or Cleaner/Applications/Firefox or whatever, and running CCleaner.
The reason I asked the question on the forum was because I could swear that I ran CCleaner specifically to see if that would clear out the list of cookies to delete, but it didn't. Obviously I must have made some simple mistake; maybe I had the Firefox check box accidentally unchecked. Duh.
In any event, all I wanted to do was what my question asked: to clear out the "Cookies to Delete" field. Everyone over-thought the question because they couldn't imagine that anyone would ask such an obvious question!...but I did.
Thanks a lot for all your comments. It was amusing to read the creative interpretations of what I might have been up to!
papyrus