I found this while trying to remember something I read in the Jolly Roger Cookbook (a version of the Anarchist Cookbook that was making its way around the pre-Internet back in the day). Thankfully I never tried anything out of it, because 13-year-old me did not have as refined a bullshit detector as current me.

As an aside, I am just old enough to have caught the tail end of the phreaking scene, and have seen a blue box used in practice from a pay phone. Good times.