diff --git a/lib/Magomogo/Persisted/AbstractProperties.php b/lib/Magomogo/Persisted/AbstractProperties.php
index cdcc47c..893a39c 100644
--- a/lib/Magomogo/Persisted/AbstractProperties.php
+++ b/lib/Magomogo/Persisted/AbstractProperties.php
@@ -42,12 +42,6 @@ public function id($container)
             $this->idInContainer[get_class($container)] : null;
     }
 
-    public function resetPersistency()
-    {
-        $this->idInContainer = array();
-        return $this;
-    }
-
     public function naturalKey()
     {
         return null;
diff --git a/lib/Magomogo/Persisted/PropertiesInterface.php b/lib/Magomogo/Persisted/PropertiesInterface.php
new file mode 100644
index 0000000..16852e4
--- /dev/null
+++ b/lib/Magomogo/Persisted/PropertiesInterface.php
@@ -0,0 +1,64 @@
+<?php
+namespace Magomogo\Persisted;
+
+use Magomogo\Persisted\Container\ContainerInterface;
+
+interface PropertiesInterface
+{
+    /**
+     * Returns unique identifier in given container
+     *
+     * @param ContainerInterface $container
+     * @return mixed
+     */
+    public function id($container);
+
+    /**
+     * Optionally defines natural key value
+     * null value forces container to set its artificial identifier
+     *
+     * @return mixed
+     */
+    public function naturalKey();
+
+    /**
+     * The message. A container stored properties giving particular identifier
+     *
+     * @param mixed $id
+     * @param ContainerInterface $container
+     */
+    public function persisted($id, $container);
+
+    /**
+     * Load all values from the container
+     *
+     * @param ContainerInterface$container
+     * @param mixed $id
+     * @return $this
+     */
+    public function loadFrom($container, $id);
+
+    /**
+     * Save all value to the container
+     *
+     * @param ContainerInterface $container
+     * @return string unique identifier
+     */
+    public function putIn($container);
+
+    /**
+     * Delete this properties form the container
+     *
+     * @param ContainerInterface $container
+     * @return void
+     */
+    public function deleteFrom($container);
+
+    /**
+     * Copy state to another properties of same type
+     *
+     * @param self $properties
+     * @return self
+     */
+    public function copyTo($properties);
+}
diff --git a/test/Persisted/AbstractPropertiesTest.php b/test/Persisted/AbstractPropertiesTest.php
index e040191..4c56074 100644
--- a/test/Persisted/AbstractPropertiesTest.php
+++ b/test/Persisted/AbstractPropertiesTest.php
@@ -88,14 +88,6 @@ public function testIssetMagicMethod()
         $this->assertFalse(isset(self::properties()->not_existing));
     }
 
-    public function testPersistencyCanBeReset()
-    {
-        $bag = self::properties();
-        $bag->persisted(88, new \stdClass());
-        $this->assertEquals(88, $bag->id(new \stdClass()));
-        $this->assertNull($bag->resetPersistency()->id(new \stdClass()));
-    }
-
 //----------------------------------------------------------------------------------------------------------------------
 
     private static function properties()
diff --git a/test/Persisted/Container/MemoryTest.php b/test/Persisted/Container/MemoryTest.php
index e0e2814..ebc34c4 100644
--- a/test/Persisted/Container/MemoryTest.php
+++ b/test/Persisted/Container/MemoryTest.php
@@ -106,7 +106,7 @@ public function testCanSaveAndLoadAJobRecord()
         $jobRecord = new JobRecord\Model(ObjectMother\Company::xiag(), ObjectMother\Company::nstu());
         $id = $jobRecord->save($container);
 
-        $this->assertModelsAreEqual(
+        $this->assertEquals(
             $jobRecord,
             JobRecord\Model::load($container, $id)
         );
@@ -128,17 +128,4 @@ public function testProvidesCorrectInstanceOfAggregatedProperties()
             $personProperties->creditCard->paymentSystem()
         );
     }
-
-    /**
-     * @param ModelInterface $model1
-     * @param ModelInterface $model2
-     */
-    private function assertModelsAreEqual($model1, $model2)
-    {
-        $container = new Memory();
-        $this->assertEquals(
-            $container->exposeProperties($model1)->resetPersistency(),
-            $container->exposeProperties($model2)->resetPersistency()
-        );
-    }
 }