Three hundred years ago our ancestors were just as inventive. Rudimentary condoms have been found amongst the excavations at Dudley Castle. The castle surrendered in 1646 and amongst the belongings of the beleaguered inhabitants was a bundle of five used condoms made of fish or animal intestines. Obviously they were expecting a long siege. In days when securing the heir to the dynasty was paramount these were used as a protection against disease rather than to prevent birth. .
Salt damages the concrete pillars that carry motorway traffic.
Animal urine is an excellent substitute and has none of the side effects, but unfortunately costs ten times as much. I don't know why.