diff --git a/elm.json b/elm.json
index 88f17b0..cbfa04e 100644
--- a/elm.json
+++ b/elm.json
@@ -3,7 +3,7 @@
     "name": "linsyking/messenger-core",
     "summary": "Core library for Messenger.",
     "license": "BSD-3-Clause",
-    "version": "4.1.0",
+    "version": "5.0.0",
     "exposed-modules": {
         "Definitions": [
             "Messenger.Recursion",
diff --git a/src/Messenger/Recursion.elm b/src/Messenger/Recursion.elm
index d85282b..255acf4 100644
--- a/src/Messenger/Recursion.elm
+++ b/src/Messenger/Recursion.elm
@@ -1,5 +1,5 @@
 module Messenger.Recursion exposing
-    ( Updater, Matcher, Super
+    ( Updater, Matcher, Super, Cleaner
     , RecBody
     )
 
@@ -10,7 +10,7 @@ module Messenger.Recursion exposing
 
 This module provides the signature for the updater
 
-@docs Updater, Matcher, Super
+@docs Updater, Matcher, Super, Cleaner
 @docs RecBody
 
 -}
@@ -38,6 +38,12 @@ type alias Super d =
     d -> Bool
 
 
+{-| Clean the environment
+-}
+type alias Cleaner c =
+    c -> c
+
+
 {-| RecBody type.
 
 Pass this as an argument to the updater
@@ -47,4 +53,5 @@ type alias RecBody a b c d =
     { update : Updater a b c d
     , match : Matcher a d
     , super : Super d
+    , clean : Cleaner c
     }
diff --git a/src/Messenger/RecursionArray.elm b/src/Messenger/RecursionArray.elm
index 6e8d684..9b014a4 100644
--- a/src/Messenger/RecursionArray.elm
+++ b/src/Messenger/RecursionArray.elm
@@ -32,7 +32,7 @@ updateObjects rec env msg objs =
         ( newObjs, ( newMsgUnfinished, newMsgFinished ), newEnv ) =
             updateOnce rec env msg objs
     in
-    updateRemain rec newEnv ( newMsgUnfinished, newMsgFinished ) newObjs
+    updateRemain rec (rec.clean newEnv) ( newMsgUnfinished, newMsgFinished ) newObjs
 
 
 {-| Recursively update all the objects in the Array, but also uses target
diff --git a/src/Messenger/RecursionList.elm b/src/Messenger/RecursionList.elm
index a5f1dfd..59cbc28 100644
--- a/src/Messenger/RecursionList.elm
+++ b/src/Messenger/RecursionList.elm
@@ -31,7 +31,7 @@ updateObjects rec env msg objs =
         ( newObjs, ( newMsgUnfinished, newMsgFinished ), newEnv ) =
             updateOnce rec env msg objs
     in
-    updateRemain rec newEnv ( newMsgUnfinished, newMsgFinished ) newObjs
+    updateRemain rec (rec.clean newEnv) ( newMsgUnfinished, newMsgFinished ) newObjs
 
 
 {-| Recursively update all the objects in the List, but also uses target