Rated 4 out of 5 stars

What happens is that I delete a particular cookie and it appears again very soon afterwards when I reuse my Firefox. Therefore, you should allow a previously deleted cookie to be deleted permanently after it has been deleted once. A kind of option saying "delete permanently". Ex: yadroo.ru.etc, m.webtrends.com.etc, and more.

This review is for a previous version of the add-on (1.5.1). 

That feature is available since 1.2
Either right click on a selected cookie and chose "Delete and block" or press SHIFT + DELETE