diff --git a/src/taoensso/nippy.clj b/src/taoensso/nippy.clj
index c21f83c..e3c32a9 100644
--- a/src/taoensso/nippy.clj
+++ b/src/taoensso/nippy.clj
@@ -834,87 +834,6 @@
     (mapv meta
       (thaw (freeze [(cache v1) (cache v2) (cache v1) (cache v2)])))))
 
-;;;; Semi-automatic caching ; Experimental
-
-(deftype CachedKeys [val recursive?])
-(defn cache-keys
-  "Experimental! Wraps map so that keyword, symbol and string keys will
-  automatically use `cache` during serialization."
-  ([x           ] (cache-keys x false))
-  ([x recursive?]
-   (if (instance? CachedKeys x)
-     (let [^CachedKeys x x
-           r? (.-recursive? x)]
-       (if (= recursive? r?)
-         x
-         (CachedKeys. (.-val x) recursive?)))
-
-     (when (enc/some? x)
-       (CachedKeys. (enc/have map? x) recursive?)))))
-
-(defmacro ^:private auto-cache-val [v] `(if (map? ~v) (cache-keys ~v) ~v))
-(defmacro ^:private auto-cache-key [k]
-  `(cond*
-     (keyword? ~k) (if (instance? Cached ~k) ~k (Cached. ~k))
-     (string?  ~k) (if (instance? Cached ~k) ~k (Cached. ~k))
-     (symbol?  ~k) (if (instance? Cached ~k) ~k (Cached. ~k))
-     :else     ~k))
-
-(defn- write-cached-kvs
-  ([^DataOutput out id-lg ^CachedKeys x]
-   (let [coll       (.-val        x)
-         recursive? (.-recursive? x)
-         cnt (count coll)]
-
-     (write-id       out id-lg)
-     (write-lg-count out cnt)
-     (if recursive?
-       (-run-kv!
-         (fn [k v]
-           (-freeze-with-meta! (auto-cache-key k) out)
-           (-freeze-with-meta! (auto-cache-val v) out))
-         coll)
-
-       (-run-kv!
-         (fn [k v]
-           (-freeze-with-meta! (auto-cache-key k) out)
-           (-freeze-with-meta!                 v  out))
-         coll))))
-
-  ([^DataOutput out id-empty id-sm id-md id-lg ^CachedKeys x]
-   (let [coll       (.-val        x)
-         recursive? (.-recursive? x)
-         cnt (count coll)]
-
-     (if (zero? cnt)
-       (write-id out id-empty)
-       (do
-         (cond*
-           (sm-count? cnt)
-           (do (write-id       out id-sm)
-               (write-sm-count out cnt))
-
-           (md-count? cnt)
-           (do (write-id       out id-md)
-               (write-md-count out cnt))
-
-           :else
-           (do (write-id       out id-lg)
-               (write-lg-count out cnt)))
-
-         (if recursive?
-           (-run-kv!
-             (fn [k v]
-               (-freeze-with-meta! (auto-cache-key k) out)
-               (-freeze-with-meta! (auto-cache-val v) out))
-             coll)
-
-           (-run-kv!
-             (fn [k v]
-               (-freeze-with-meta! (auto-cache-key k) out)
-               (-freeze-with-meta!                 v  out))
-             coll)))))))
-
 ;;;;
 
 (id-freezer nil        id-nil)