Here is a sample contextual menu with several clips from different applications:

 

When you choose "Add Clipboard Content..." a dialog is displayed and you may enter clip name and submenu name:

 

New contextual menu configuration after adding a new clip with names as shown in the dialog above:

 

You may remove clips from your collection using "option" key when selecting given item.
When you press "option" key after the contextual menu is shown the look of menu items changes telling you that selecting an item will remove it from the list.

 

In addition to saving current clipboard content you may save a selected text from any editor that supports contextual menus.
The difference between selected text and clipboard content is that the clipboard usually contains styled text. Sometimes you may want to copy just the plain text without style and you can do it using "Add Selected Text..." option.