Flush Drupal 7's cache, when all you have is FTP (!) access.

flush.php

<?php
error_reporting(-1);
ini_set('display_errors', 'On');
define('DRUPAL_ROOT', getcwd());
require_once DRUPAL_ROOT . '/includes/bootstrap.inc';
drupal_bootstrap(DRUPAL_BOOTSTRAP_FULL);
drupal_flush_all_caches();
print 'All caches cleared';