--- smtp.install	2009-05-04 03:41:37.000000000 -0300
+++ smtp.install	2009-05-04 03:41:25.000000000 -0300
@@ -20,6 +20,9 @@ function smtp_uninstall() {
   variable_del('smtp_protocol');
   variable_del('smtp_test_address');
   variable_del('smtp_username');
+  variable_del('smtp_pop_port');
+  variable_del('smtp_pop_host');
+  variable_del('smtp_auth_method');
 
   if (variable_get('smtp_library', '') == drupal_get_path('module', 'smtp') .'/smtp.module') {
     variable_del('smtp_library');