I plan to erase and reinstall Yosemite as a last ditch effort to get rid of some major issues after installing Yosemite. I will then restore from a Time Machine backup. My question is, I'm sure I have collected a lot of junk in my OS over the years (long unused prefs files, etc.) and I'd rather not restore any of that junk back to my computer. When restoring from a Time Machine backup, does it include all the junk system files, and if so is there a way to get a clean reinstall?