diff --git a/permissions/__init__.py b/permissions/__init__.py
index e69de29..e2f35f6 100644
--- a/permissions/__init__.py
+++ b/permissions/__init__.py
@@ -0,0 +1 @@
+default_app_config = 'permissions.apps.PermissionsConfig'
diff --git a/permissions/apps.py b/permissions/apps.py
new file mode 100644
index 0000000..2d251db
--- /dev/null
+++ b/permissions/apps.py
@@ -0,0 +1,10 @@
+from django.apps import AppConfig
+
+
+class PermissionsConfig(AppConfig):
+
+    name = 'permissions'
+    verbose_name = 'Permissions'
+
+    def ready(self):
+        import permissions.signals
diff --git a/permissions/models.py b/permissions/models.py
index 240c6e3..be11fcb 100644
--- a/permissions/models.py
+++ b/permissions/models.py
@@ -1,6 +1,7 @@
 from django.db import models
 from django.db.models import Q
 from django.utils.encoding import python_2_unicode_compatible
+from django import VERSION
 
 from tracker.models import Project
 from accounts.models import *
@@ -68,7 +69,6 @@ class PermissionModel(models.Model):
     @property
     def type(self):
         return self.get_grantee_type_display()
-#        return dict(self.GRANTEE_TYPE)[self.grantee_type]
 
     @property
     def name(self):
@@ -142,3 +142,7 @@ class ProjectPermission(PermissionModel):
     def __str__(self):
         return self.grantee.__str__() + "'s permissions on " \
             + self.project.name + " project"
+
+
+if VERSION < (1, 7):
+    import tracker.signals
diff --git a/permissions/signals.py b/permissions/signals.py
new file mode 100644
index 0000000..1d11576
--- /dev/null
+++ b/permissions/signals.py
@@ -0,0 +1,50 @@
+from django.db.models.signals import pre_delete
+from django.dispatch import receiver
+
+from accounts.models import *
+from permissions.models import *
+
+
+"""
+As permissions objects do not use a foreign key but instead an integer field
+on the foreign object id, we can rely on database cascade deletion to delete
+outaded permissions and we have to do it our-self.
+"""
+
+@receiver(pre_delete, sender=User, dispatch_uid="clean_user_perms")
+def clean_user_perms(sender, instance, **kwargs):
+    # Clean global permissions
+    perms = GlobalPermission.objects.filter(grantee_id=instance.id,
+            grantee_type=GlobalPermission.GRANTEE_USER)
+    perms.delete()
+    # Clean project permissions
+    perms = ProjectPermission.objects.filter(grantee_id=instance.id,
+            grantee_type=GlobalPermission.GRANTEE_USER)
+    perms.delete()
+
+
+@receiver(pre_delete, sender=Group, dispatch_uid="clean_group_perms")
+def clean_group_perms(sender, instance, **kwargs):
+    # Clean global permissions
+    perms = GlobalPermission.objects.filter(grantee_id=instance.id,
+            grantee_type=GlobalPermission.GRANTEE_GROUP)
+    perms.delete()
+    # Clean project permissions
+    perms = ProjectPermission.objects.filter(grantee_id=instance.id,
+            grantee_type=GlobalPermission.GRANTEE_GROUP)
+    perms.delete()
+
+
+@receiver(pre_delete, sender=Team, dispatch_uid="clean_team_perms")
+def clean_team_perms(sender, instance, **kwargs):
+    print(instance)
+    print(instance.id)
+    # Clean global permissions
+    perms = GlobalPermission.objects.filter(grantee_id=instance.id,
+            grantee_type=GlobalPermission.GRANTEE_TEAM)
+    print(perms)
+    perms.delete()
+    # Clean project permissions
+    perms = ProjectPermission.objects.filter(grantee_id=instance.id,
+            grantee_type=GlobalPermission.GRANTEE_TEAM)
+    perms.delete()