diff --git a/boost.module b/boost.module
index 7ca2bba..7e75f8b 100644
--- a/boost.module
+++ b/boost.module
@@ -310,14 +310,12 @@ function boost_exit($destination = NULL) {
  */
 function boost_cron() {
   // Remove expired files from the cache.
-  global $_boost;
 
   // This was not invoked in hook_init because of the quick check to
-  // avoid caching requests from the CLI
-  $_boost = boost_transform_url();
 
-  if (isset($_boost['base_dir']) && variable_get('boost_expire_cron', BOOST_EXPIRE_CRON)) {
-    $count = _boost_rmdir($_boost['base_dir'], FALSE);
+  if (variable_get('boost_expire_cron', BOOST_EXPIRE_CRON)) {
+    $cache_dir = variable_get('boost_root_cache_dir', BOOST_ROOT_CACHE_DIR) . '/' . variable_get('boost_normal_dir', BOOST_NORMAL_DIR);
+    $count = _boost_rmdir($cache_dir, FALSE);
     watchdog('boost', 'Expired %count stale files from static page cache.', array('%count' => $count), WATCHDOG_NOTICE);
   }
 }