Erasing drive to sell iMac
I tried to erase the hard drive since I am selling my iMac. However, I held down the command and R keys and after the restart I was back at the desktop. I pulled up Disk Utilites but my only options seem to be greyed out. The only option is erase free space (which I did) and then when I reisntalled the OS I was back at my own desktop with all of my apps after restart. How do I erase everything and get it back to factory specs for resell? Thank you.
21.5" iMac purchased 12/2013
OS X - 10.8.5
Proc. 2.96GHz, Intel Core i5
iMac, OS X Mountain Lion (10.8.4)