diff --git a/core/modules/system/system.admin.inc b/core/modules/system/system.admin.inc
index 6dca80b..de069f6 100644
--- a/core/modules/system/system.admin.inc
+++ b/core/modules/system/system.admin.inc
@@ -672,6 +696,11 @@ function _system_theme_settings_validate_path($path) {
  * Process system_theme_settings form submissions.
  */
 function system_theme_settings_submit($form, &$form_state) {
+  // Exclude unnecessary elements before saving.
+  form_state_values_clean($form_state);
+  $key = $form_state['values']['var'];
+  unset($form_state['values']['var']);
+
   $values = $form_state['values'];
 
   // If the user uploaded a new logo or favicon, save it to a permanent location
@@ -703,10 +732,7 @@ function system_theme_settings_submit($form, &$form_state) {
   if (empty($values['default_favicon']) && !empty($values['favicon_path'])) {
     $values['favicon_mimetype'] = file_get_mimetype($values['favicon_path']);
   }
-  $key = $values['var'];
 
-  // Exclude unnecessary elements before saving.
-  unset($values['var'], $values['submit'], $values['reset'], $values['form_id'], $values['op'], $values['form_build_id'], $values['form_token']);
   variable_set($key, $values);
   drupal_set_message(t('The configuration options have been saved.'));