This post explains all the steps required to do a factory reset to a Mac running OS X 10.9 (Mavericks). These steps can also be used on other lower mac versions.
Apple OS X 10.9.2 Mavericks (for Mac) Review
Mavericks not available to restore the OS… - Apple Community
Kon Boot MAC, PDF, Mac Os
How to proceed? Reinstall OS X Mavericks … - Apple Community
Mac OS X 10.9 Mavericks review - The Verge
Revisions, PDF, Java (Programming Language)
売れ筋 i Mac OS Mavericks 10.9.4 PC/タブレット
売れ筋 i Mac OS Mavericks 10.9.4 PC/タブレット
How to reset a Mac password if you forgot (OS X Mavericks)
OS X 10.9 Mavericks: Will Adobe software work?, conrad chavez
23 Years of Mac OS X Design History - 59 Images - Version Museum
Pro Git
Install Mac OS X 10.9 Maverics on a PC (Hackintosh) with AMD FX
Pro Git