[FL8] Shared objects quick question

I had been wondering how to use shared objects for a long time and thanks a million to this mini-tut: http://www.kirupa.com/developer/actionscript/shared_objects.htm
I know how. The only thing is it says that to clear a shared object, you must type (used in his example)

user_so.clear();

but what if i wanted to delete a certain block of data on it, for example I have the shared object user.
And i don’t want to delete all of it, but just one block of data (specifically user.data.doc)

I tried

user.doc.clear();

and

user.data.doc.clear();

and neither worked, how would I do this?

~ Thanks in advance