diff --git a/apps/files/cron.py b/apps/files/cron.py
index 78aa0878ee0..a76c8b370f9 100644
--- a/apps/files/cron.py
+++ b/apps/files/cron.py
@@ -1,9 +1,11 @@
+import hashlib
 import os
 import shutil
 import stat
 import time
 
 from django.conf import settings
+from django.core.cache import cache
 
 import cronjobs
 import commonware.log
@@ -17,8 +19,22 @@ def cleanup_extracted_file():
     log.info('Removing extracted files for file viewer.')
     root = os.path.join(settings.TMP_PATH, 'file_viewer')
     for path in os.listdir(root):
-        path = os.path.join(root, path)
-        age = time.time() - os.stat(path)[stat.ST_ATIME]
+        full = os.path.join(root, path)
+        age = time.time() - os.stat(full)[stat.ST_ATIME]
         if (age) > (60 * 60):
-            log.info('Removing extracted files: %s, %dsecs old.' % (path, age))
-            shutil.rmtree(path)
+            log.info('Removing extracted files: %s, %dsecs old.' % (full, age))
+            shutil.rmtree(full)
+            # Nuke out the file and diff caches when the file gets removed.
+            id = os.path.basename(path)
+            try:
+                int(id)
+            except ValueError:
+                continue
+            for prefix in ['file-viewer-get-deleted-files',
+                           'file-viewer-get-files',
+                           'file-viewer']:
+                key = hashlib.md5()
+                key.update(str(id))
+                cache.delete('%s:memoize:%s:%s' % (settings.CACHE_PREFIX,
+                                                   prefix, key.hexdigest()))
+            log.info('Removing cache file-viewer cache entries for: %s' % id)
diff --git a/apps/files/helpers.py b/apps/files/helpers.py
index 27bd508cc0c..28b1234f39e 100644
--- a/apps/files/helpers.py
+++ b/apps/files/helpers.py
@@ -189,12 +189,16 @@ def get_files(self):
         addon-file. Full of all the useful information you'll need to serve
         this file, build templates etc.
         """
+        if self._files:
+            return self._files
+
         if not self.is_extracted():
             return {}
         # In case a cron job comes along and deletes the files
         # mid tree building.
         try:
-            return self._get_files()
+            self._files = self._get_files()
+            return self._files
         except (OSError, IOError):
             return {}
 
@@ -281,7 +285,7 @@ def __init__(self, left, right):
         self.key = None
 
     def __str__(self):
-        return '%s:%s' % (self.left, self.right)
+        return str(self.left)
 
     def extract(self):
         self.left.extract(), self.right.extract()