code: public function deleteExpiredRequests()
      {
          $helper = Mage::helper('sheep_debug');
          if (!$helper->isEnabled()) {
              return 'skipped: module is disabled.';
          }
  
          if ($helper->getPersistLifetime() == 0) {
              return 'skipped: lifetime is set to 0';
          }
  
          $expirationDate = $this->getExpirationDate(date(self::DATE_FORMAT));
          $table = $this->getRequestsTable();
          $deleteSql = "DELETE FROM {$table} WHERE date <= '{$expirationDate}'";
  
          /** @var Magento_Db_Adapter_Pdo_Mysql $connection */
          $connection = Mage::getSingleton('core/resource')->getConnection('core_write');
  
          /** @var Varien_Db_Statement_Pdo_Mysql $result */
          $result = $connection->query($deleteSql);
          return "{$result->rowCount()} requests deleted";
      }
docs: Cron jobs that deletes expired request info