How do I clean galvanized metal burglar bars?

Hello, I have the following burglar bars on my windows at my house: Attachment 42585 (http://www.doityourself.com/forum/attachments/cleaning-plus-mold-mildew-stain-removal/42585-how-do-i-clean-galvanized-metal-burglar-bars-2014-11-30-15.22.17.jpg) Up close they look like this: Attachment 42586 (http://www.doityourself.com/forum/attachments/cleaning-plus-mold-mildew-stain-removal/42586-how-do-i-clean-galvanized-metal-burglar-bars-2014-11-30-15.22.30.jpg)