diff --git a/spec/HydrateSpec.js b/spec/HydrateSpec.js
index ef7cac8..990b773 100644
--- a/spec/HydrateSpec.js
+++ b/spec/HydrateSpec.js
@@ -28,6 +28,15 @@ describe("Hydrate", function() {
   }
   extend(BasicSubclass, BasicClass);
 
+  it("should cleanup hydrate properties", function() {
+    var input = {}
+    var basic = {f:[{a:{}}]}
+    input.objArray = [{}, basic, {}];
+    input.basic = basic;
+    input.objHash = {a: {}, b: basic, c: {}};
+    expect(hydrate.parse(hydrate.stringify(input))).toEqual(input);
+  });
+
   it("should serialize primitives", function() {
     var inputs = [undefined, null, 3, "foo", ["a", 3, "bar"], true, false]
     for(var i = 0; i < inputs.length; i++){
diff --git a/src/hydrate.coffee b/src/hydrate.coffee
index 56bd250..565743c 100644
--- a/src/hydrate.coffee
+++ b/src/hydrate.coffee
@@ -245,6 +245,10 @@ scope = this
     # Also, runs migrations.
     # Private.
     clean: (o, cleaned=[]) ->
+      # if its not an object then there is no cleaning to do
+      if o == null || typeof o != "object" then return true
+      # if we have already cleaned this object then return
+      if !Util.isArray(o) && cleaned.indexOf(o) > -1 then return true
       # migrate
       migrations = @migrations[o.__hydrate_cons]
       if(o.version? &&
@@ -253,15 +257,18 @@ scope = this
         for num in [o.version..migrations.length - 1]
           migrations[num].call(o)
         delete o.version
-
+      # do actual clean
       cleaned.push o
-      if typeof o == "object" && !Util.isArray(o)
+      if Util.isArray(o)
+        for i in o 
+          @clean(i, cleaned)
+      else # o is an object
         for k, v of o
           if k == "__hydrate_id" || k == "__hydrate_cons"
             delete o[k]
-          else if typeof v == "object" && v && !Util.isArray(o) && cleaned.indexOf(v) < 0
+          else
             @clean(v, cleaned)
-      true
+      return true
 
     # Declare a migration for an object -- this will automatically run callbacks
     # on old objects to get them in sync with current Javascript classes.