Okay, we use the @ tab of the data card pretty exclusively so when data is entered on the configuration specific tabs it wreaks havoc on our users.  I have a few parts that have been checked into the vault with configuration specific properties that I would like to remove, so I do this:

Check out the file

open the properties window

navigate to the custom properties tab

remove the unwanted properties entirely

rebuild, save

view the data card to see my changes have remove the properties from tabs other than the @ tab

check the file in

The problem is when I view the data card after all of this the properties still exist...???  Where is the option to clear the values?