Have you tried clojure.string
?
(use '[clojure.string :only (split)])
(split "clojure8*)-6contrib&(*does^&$not*_^%exist^*#anymore" #"[^a-zA-Z]+")
=> ["clojure" "contrib" "does" "not" "exist" "anymore"]
BTW all clojure.contrib
have been migrated to separated libraries http://dev.clojure.org/display/design/Where+Did+Clojure.Contrib+Go