Hi, I want to try to sell my early 2009 mac pro and a c2005 Powermac G5. ( and my '07, 09, and '11 MBPs!) What should I do to prepare them for sale in terms of wiping my data and password from the hard drives yet making sure they have the most current as possible OSX and standard apps installed ( iLife, etc). Should I remove my drives and buy fresh HDDs? (I realize the G5 is very old, and I believe the last OS available for 2009 mac is sierra(?) I likely have a few OS install discs on hand, but in recent years, all osx upgrades have been downloads. If you can offer advice, with sepcific osx versions for each machine etc, i'd greatly appreciate it.