I recently posted something about a 1940s era junkman who visited my neighborhood and how my mother always looked for old pots and pans which she would repair with little pieces of metal. My daughter found this card of Mendets on eBay and bought it for me. This is exactly what my mother used, except sometimes she bought them in a small box.
Mendets were patented in the early 1900s and the dress/hairstyle of the lady on the card makes me think this might be from the 1930s. The back of the card has instructions as well as suggesting some other uses such as repairing a hot water bottle, using on campfire utensils and even shows a lady perched precariously on a ladder repairing a gutter (“Saved the cost of a tinsmith”).
Until World War II was over, I believe every pot, pan and kettle in our kitchen had a Mendet or two helping to give a bit more life.
Click on photos to enlarge.