diff --git a/swh/scheduler/celery_backend/config.py b/swh/scheduler/celery_backend/config.py
--- a/swh/scheduler/celery_backend/config.py
+++ b/swh/scheduler/celery_backend/config.py
@@ -174,7 +174,7 @@
     # A string identifying the default serialization method to use.
     # Can be pickle (default), json, yaml, msgpack or any custom serialization
     # methods that have been registered with kombu.serialization.registry
-    CELERY_ACCEPT_CONTENT=['msgpack', 'json', 'pickle'],
+    CELERY_ACCEPT_CONTENT=['msgpack', 'json'],
     # If True the task will report its status as “started”
     # when the task is executed by a worker.
     CELERY_TRACK_STARTED=True,
diff --git a/swh/scheduler/task.py b/swh/scheduler/task.py
--- a/swh/scheduler/task.py
+++ b/swh/scheduler/task.py
@@ -136,7 +136,7 @@
 class Task(celery.app.task.Task, metaclass=TaskType):
     """a schedulable task (abstract class)
 
-    Sub-classes must implement the run() method.  Sub-classes that
+    Sub-classes must implement the run_task() method.  Sub-classes that
     want their tasks to get routed to a non-default task queue must
     override the task_queue attribute.