Hi jgarback,

Firefox is a web browser. It displays content from websites. The content, such as your emails, is controlled by the content providers. Who is your email provider? You would have better luck finding out how to unsubscribe to an email by consulting your email provider's documentation.

If it is email that you haven't subscribed to personally then you should never respond.
If you respond then you confirm that the email address exists and you may get a lot more such mails.
If you have an email address with a simple name or combination of names with a popular email provider that can be generated via a dictionary look up or script then that can happen quite easily.
Spammers use all kinds of scripts to send out bulk mail to addresses that they generate in the hope that someone responds.

And any "unsubscribe" button will often be a fake taking you somewhere where you don't want to go.

Do as cor-el advises - "don't respond". Also avoid the temptation to open them and have a look. Don't click on anything.

Depending on your email set-up, mark them as spam/junk and then delete them.

Be wary about where you leave your email address.

Yes, this was helpful. May I suggest that your tech people "disallow" any messages be placed on the system without an "unsubscribe option". This would avoid entries that are unsolicited which takes up our time and clogs up the system.

Your comments, please!

Firefox is a web browser not an email application and has no control over emails. I very much doubt that what you are after is possible or there would be no spam. You would need to get in touch with the likes of Hotmail, Yahoo etc etc.

Actually spam, if that's what it is, is far more dangerous with an apparent "unsubscribe" option.