It was rather simple. Make one of these things, paste four or five to a sheet of paper with a glue stick. Copy 500 of them at work. Cut all 2000 at work or whatever and hit the mail. Every letter or Zine you sent out you threw some in, as well as the others you received from other mags/bands/labels. This was how it was done for many, many years.
Fuckin' fancy computers!