An unusual place to display advertisements was on the back of postage stamps. People were invited to contemplate their buying needs before licking and sticking. The New Zealand Post Office introduced these in 1893, but the practice did not last as people were concerned that licking the dye might poison them.
Te whakamahi i tēnei tūemi
Permission of the Alexander Turnbull Library, National Library of New Zealand, Te Puna Mātauranga o Aotearoa, must be obtained before any re-use of this image.