I am sending them a business reply envelope with the reply form, on which I have written, "No thanks. Please stop wasting paper and my time."
I have also enclosed the following: Four CDs, edges broken off so they'll fit (3 of them AOL CDs); two metal brackets, ends broken off so they'll fit; and a handful of pennies. I taped it shut with packing tape, and taped over the window also, so none of it will fall out.
It weighs in at about half a pound (masses in at 229 grams). Postage will be paid by addressee, it says. I wonder if they'll keep trying to get me to sign up now.