Using disj to remove an element from a set in Clojure

Question

Hi I've hit a brick wall whilst trying to remove an element from a set.

I have a map of cards.

   (def cards
  {
    :card1 {:name "Wisp"              :type "Monster"     :damage 1 :health 1 :cost 0 :charge "t"}
    :card2 {:name "Spider Tank"       :type "Monster"     :damage 3 :health 4 :cost 3}
    :card3 {:name "Boulder Fist Ogre" :type "Monster"     :damage 6 :health 7 :cost 6}

    }
 )

And a deck (set) of these cards.

(def deck1 (set (map cards '(:card1 :card2 :card3))))

When I use disj to try and remove one of these cards nothing happens.

(disj deck1 :card1)

I really have no idea why.

Answer 1

leetwinski was right in the comments. (disj deck1 (:card1 cards)) is correct.