The recommended practice is to set up the content center to use your part/stock/etc. numbers/descriptions/etc.
There have been many posts in the past from people trying to edit the content center. From them I got the impression that it wasn't easy. Plus our numbering system is not the best and would require paying careful attention to each nut and bolt, etc.
I also edit the iProperties on a bolt by bolt basis, so I know that still works. Are you opening the cc parts? I do it in the assembly environment, right click the bolt (it's a pain when they're patterned you have to go into the browser and expand the pattern to select one) and pick properties then type in what you need and close that window. Then when you save the assembly click the "No(Library)" to change it to yes.
Do you have "Do not list referenced files that default to "No" in the Save dialog" checked on the save tab of application options? That might prevent you from saving them.
Now, I have a problem with this method. It might just be fasteners I haven't changed since we upgraded but it seems like it doesn't stick. Just about every job I come across one or two fasteners with the default description, etc.. They usually have a coworker's name in Designer and/or Author so I'm assuming that when he is placing them they are overwriting my corrected properties in the community cc.
Libraries may be located anywhere on your system or network OUTSIDE your
project search path. As a result the content center folders and library folders
are flagged as read-only within the current project.
In order to create a project that will allow you to edit those same library
folders, you will need to place a project file (IPJ) in the top-level Library
folder. When that is done, that folder and all subfolders underneath the Library
folder will be editable.