Well, E*Trade finally responded to my e-mail inquiry, ten days after it was submitted:
Dear Mr. [MyMoneyBlog]:
Thank you for your inquiry, Enron Corp. is currently being held in your account as a worthless security. In order to remove it from your account you must send us the Worthless Security Authorization Form. You can find this form under Accounts>Forms & Applications>Trading & Tax>Worthless Security Authorization Form. There is a $5 processing fee in order to complete your request which will be automatically debited from your account.
And they had one of those usually-annoying surveys at the end, which I gladly filled out this time. I wonder if I’ll get any response. The answer to the question was satifactory, and the fee is pretty standard. Hopefully it can be processed by the end of the year.