Delete Old Time Machine Backups

Recently I get several Time Machine warning messages about my TM is full. My mac's disk space is about 271GB in use and my TM is 500GB. I have to either update my USB TM to bigger size or I have to delete some old backups. Before I go the former solution, I think the later one is quick solution for me, since I know my oldest backups can be removed without any concern.

Although the deletion is very easy and straightforward, I did not find it through TM UI when I went to my TM history. I quickly found the way by googling. Here is a snapshot of the menu item from a backup:


The Action menu list provides deleting and restoring actions depending on the current selections as well. For example, if I select a file, I can delete it from TM or restore it back to my current OS.

By the way, TM does not allow me take a selection screenshot by Shift-Command-4, but I can do whole screen snapshot (S-C-3). Then I take a selection screenshot from the image's quick view.