I want to drop two crafting books but I cannot.

I, Mishani Akuma on Leviathan was almost capped on red crafting scripts. Without thinking about it since the game had gotten so much better at not letting you buy duplicate untradeable items I bought the carpentry book V and the black smith book V. I then remembered a time when I was buying these books to use up red script but couldn't use them because I was not level 70 in my crafting. A search on the item confirmed it, I already had those books on one of my retainers. The red script is not the problem, I messed up, my bad. My problem is I cannot discard any of these books let alone my duplicates. I would like to free up those two inventory spaces but the discard option is greyed out and unselectable, and I am stuck with extra books I cannot use.

Thanks.

if you haven't used the books you must use them in order to discard the duplicates.