Hello, I have let Time Machine automatically back up my computer for a few years w/o even thinking about it or managing it. Now a 1TB external is almost full. I was doing my research and read that I can just go into "Backups.backupdb" folder and delete whatever back ups I want manually. It looks like I have a few back ups every month dating back to Sept. 2011! Needless to say, I want to delete 70% of these back ups. Is it safe to just delete the old folders and leave the newer ones? I hope it's really that simple, please let me know.