To close those folders from viewing aka trolling I always drop a file called index.html with nothing in the file. Just open notepad on your computer then save the file as index.html and FTP it to those folders. Anyone trying to troll your folders will just get a blank web page.
Do NOT put that file in any folder that has a file named index.html, index.htm, index.php and so on in it.
Once again always backup your folders before making any changes
