These cards appeared in the mid-nineteenth century and were generally cheap and poorly printed, although the mechanical example above, posted on Valentine's Day 1859, is a little more elaborate. Its verse is typical:
Although you do dress rather smart, I fear you catch not lover's heart. The language of your eyes is speechless;I wish your mouth would really screech less. No nods, nor becks, nor wreathed smiles,That you can give, my heart beguiles;For love, it may with truth be said,Was out of town when you were made.The cards might target particular occupations, or be directed at personal characteristics of the recipient. Add an inexpensive stamp and the anonymity central to the valentine's tradition, and a cruel insult could be sent with little effort or risk of detection.
Unsurprisingly, such cards were often not kept or recorded by their recipients. As a result, although it is known that about half of valentines' cards in the mid-century USA were 'vinegar', we don't know if the same proportions applied in Britain.
The cards were unpopular with many commentators, who found them vulgar, unpleasant and morally damaging. It would take a drastic decline in the popularity of all valentine's cards in the early twentieth century, though, for the genre to disappear. When the giving of love tokens revived in popularity, this unpleasant counterpart remained in thankful obscurity.
Further reading: Annebella Pollen, Love Letters and Hate Mail. Norfolk Museums have several examples.