I’ve just done this very exercise for one of the sites I manage.
I sent out a mailing to all subscribers and asked if they wanted to continue to receive the updates. As you can see from the image below, I asked that if they did not wish to continue, to click either Unsubscribe to unsubscribe themselves, or click Webmaster to ask me to do the task for them.
I had three people unsubscribe so they were removed from the mailing list, and thus blacklisted. As stated in the mailing, if they wished to continue to receive our news, to do nothing.
Oh, the buttons, which were hyperlinked to the Contact the Webmaster page and direct to the subscribers unsubscribe option in phplist, were created via Da Button Factory which provide free buttons for you to use.