Sonar X2 Still 'References' Deleted Items When Re-Opening Project.

I'm using Sonar X2 Producer.
 
I recall reading some time ago on how to completely clean out a current project file from deleted tracks and synths no longer needed in the project. Now I can't find that post.
 
Although I've deleted old MIDI and audio tracks and synths, I still find that when re-opening my project, Sonar still references some of those deleted items before loading up my project.
 
Can anyone advise where I can find that option to completely remove discarded items so Sonar loads the project file without whizzing through those items.
 
Thanks.