05-03-2012 12:46 PM
Welcome to the BlackBerry® Support Community Forums.
I would suggest enabling Mass Storage Mode on the BlackBerry® smartphone and then access the files from your PC to delete all at once.
The following Inside BlackBerry Help Blog on Using Your BlackBerry Smartphone as a USB Drive: http://helpblog.blackberry.com/2012/02/blackberry-
I hope the helps.