I want to remove preferences and application support files from already uninstalled apps. I have app cleaner to remove those files when I delete the application, but that only works for stuff after I installed App Cleaner. Any automated system for programs removed before I installed App Cleaner?
CleanMyMac 2 has an Uninstaller feature that includes the ability to remove leftovers from uninstalled applications.
No more Leftovers
If you used to uninstall applications by dragging them to Trash, then you have tons of apps leftovers! Find and remove them using CleanMyMac2.