A friend has this old bear trap that I think is blacksmith made. He wants to display it where it will be exposed to the weather. What should be put on the trap to protect it from the elements and not destroy the value ?

please show us the trap.

If it was made by a smith the spring steel and most likely all the forged parts were oil quenched to retain grain structure and slowly cool the steel and then temper them so a hot oil bath is basically how it became. Some of the parts may be cast also, not sure without seeing it up close, but I would guess there are some. Thats a little tough to replicate a hot oil bath with a fully intact hot trap without ruining the trap. But a common practice with knives is boiled linseed oil, I personally would wait until summer set it in direct sun all day and use warm BLO. Thats my input just from a blacksmiths view, I do not know if that would affect the value. But if hes going to display it I would think he wants to keep it, and therefore protect it, not sell it.

Thanks, I’ll try to get a picture of the trap today.