diff --git a/flashcards/models.py b/flashcards/models.py
index f6d11fc..5dd70b0 100644
--- a/flashcards/models.py
+++ b/flashcards/models.py
@@ -2,7 +2,7 @@ from math import log1p
 from math import exp
 from datetime import timedelta
 
-from gcm import GCM
+from gcm import GCM, gcm
 from django.contrib.auth.models import AbstractUser, UserManager
 from django.contrib.auth.tokens import default_token_generator
 from django.core.cache import cache
@@ -100,10 +100,13 @@ class User(AbstractUser, SimpleEmailConfirmationUserMixin):
 
     def notify(self):
         gcm = GCM(GCM_API_KEY)
-        gcm.plaintext_request(
-            registration_id=self.registration_id,
-            data={'poop': 'data'}
-        )
+        try:
+            gcm.plaintext_request(
+                registration_id=self.registration_id,
+                data={'poop': 'data'}
+            )
+        except (gcm.GCMInvalidRegistrationException, gcm.GCMMissingRegistrationException):
+            self.registration_id = None
         self.last_notified = now()
         self.save()