Vicks Vaporub Blindness Ointment, 1978

You've probably not even recovered from the excitement of the last postcard from the mayor's rare 1970s pharmaceutical collection, yet here's another bombshell.

This is the Vicks Vaporub postcard from 1978 that came free with multi-pack orders of prosthetic eyes.
Vicks Vaporub was originally invented to temporarily blind children for up to one hour while parents did things they didn't want their offspring to witness.

The original Vicks formula also contained a psychotropic ingredient that caused hallucinations, but it was withdrawn after a class of contagious children escaped from Scarfolk high-security infant school posing as alarmed peahens.