Mailing list archive issues

I've said it before, and I'll say it again: mailing list archives have their merits, but they can be a real pain. iText has a very active mailing list, but some people still don't understand the concept. When you post something to the iText mailing list, you send a mail to about 2000 addresses. Most of these addresses belong to actual people, but some of them are used to populate third party mailing-list archives: Nabble, GMANE, mail-archive,...

I don't have any control over these archives, nor do I want any control over those archives. The administrative work generated by the mailing list is boring enough already. Unfortunately, I'm still getting mails like this one:

Dear Admin,
last year I posted to your mailing list. Unfortunately I forgot to remove my personal contact information from the mail. Thus Google shows all my personal information on the first page. Could you please remove the following post from your archive and additionally contact the support of mail-archive.com for the deletion of the post in their archive? Unfortunately I can't tell them to remove the post myself.
Please let me know, when the deletion is done.
Thank you in advance!

Let me explain why this is an indecent request. My company is investing money in the development of software. Some companies are paying my company to use this software, but most companies use it for free, some legally, some illegally.
Paying customers with a support contract, can send us questions that are treated confidentially, but if you aren't a paying customer, your only recourse is the free mailing list. In spite of the fact that we aren't paid to respond on the mailing list, we try to answer as many questions as possible. So on top of the fact that they don't pay for their use of the software, many people also get help and advice for free.

But apparently that's not enough for some people.

They want us to clean up their mess. In this case, we need to remove an address that is present in the original mail, and then copied into the reply to this mail. What is asked here, is the manual removal of several mails that are over a year out from several archives (some of which we aren't even aware of).

I've answered the question with a link to the FAQ: Please delete my mail from the archives! I've recently found out that I have access to a delete button on the SourceForge archives, and I've used this button three times in the last two weeks, but that's it: the next time somebody asks me to do this, he or she will have to buy a license, or else they'll have to live with the fact that their information is out in the open.