Lemmee guess: you're going to mail them, right?
If your copies of RD are really old, the addresses
on those postage-paid reply envelopes might no longer be valid, in
which case they'll be returned to you as undeliverable (if you
provided a return address) or end up in the Post Office's "dead
letter" bin and eventually destroyed.
In my younger, more carefree days, I used to fill in magazine
subscription forms with the names and addresses of people I did not
particularly like, and drop them in the mail using the supplied
postage-paid envelopes. 
