diff --git a/tasks.py b/tasks.py
index e411f7d..2a95597 100644
--- a/tasks.py
+++ b/tasks.py
@@ -13,12 +13,6 @@ import json
 
 app = Celery('tasks', broker=flaskapp.config['CELERY_BROKER'], task_serializer='pickle')
 
-@app.task
-def remove_old_sessions():
-    Session.query.filter(Session.updated_at < (db.func.now() - timedelta(hours=48))).\
-            delete(synchronize_session=False)
-    db.session.commit()
-
 @app.task(autoretry_for=(TwitterError, URLError))
 def fetch_acc(id, cursor=None):
     acc = Account.query.get(id)
@@ -33,8 +27,6 @@ def fetch_acc(id, cursor=None):
         acc.last_fetch = db.func.now()
         db.session.commit()
 
-
-
 @app.task
 def queue_fetch_for_most_stale_accounts(min_staleness=timedelta(minutes=5), limit=20):
     accs = Account.query\
@@ -46,9 +38,6 @@ def queue_fetch_for_most_stale_accounts(min_staleness=timedelta(minutes=5), limi
         acc.touch_fetch()
     db.session.commit()
 
-app.add_periodic_task(10*60, remove_old_sessions)
-app.add_periodic_task(60, queue_fetch_for_most_stale_accounts)
-
 @app.task
 def import_twitter_archive(archive_id):
     ta = TwitterArchive.query.get(archive_id)
@@ -93,6 +82,16 @@ def import_twitter_archive_month(archive_id, month_path):
         raise e
 
 
+@app.task
+def periodic_cleanup():
+    Session.query.filter(Session.updated_at < (db.func.now() - timedelta(hours=48))).\
+            delete(synchronize_session=False)
+    TwitterArchive.query.filter(TwitterArchive.updated_at < (db.func.now() - timedelta(days=7))).\
+            delete(synchronize_session=False)
+    db.session.commit()
+
+app.add_periodic_task(6*60*60, periodic_cleanup)
+app.add_periodic_task(60, queue_fetch_for_most_stale_accounts)
 
 if __name__ == '__main__':
     app.worker_main()