In the dark ages some wire rigging had a hemp core
to "store" or retain some of the oil and presumably reduce internal corrosion
. Probably not available now. Fishermen often had large drums to immerse their rigging in heated oil which improved penetration. The car tyre trick seems to be a partly acceptable compromise.
On my ketch
the thirty year old galvanized rigging was tested where some had surface rusting (lower, closer to the sea). The inside was perfect... as new. The load testing was as per new wire. I have never used any oil or paint
on my rigging. The wires are all good, but the eyes at the ends were of a poorer quality and I paint
them with zinc paint. It works for a few years.
I met some old codgers in Fremantle (Western Australia) who had a very old wooden boat that they used for old blokes days out fishing
and whisky consumption
. The boat was antifouled using a heated coal tar mixed with some probably unmentionable poisons, and the rigging was original wire from about 1920. The wires were repainted regularly with hot coal tar as well. No wire was visible!
The advantages with galvanized rigging is that it (and the rigging screws) are very much cheaper, and if a shroud
or stay is beginning to give up the ghost, it will be obvious as the outer strands usually part with the other wires. Not so with stainless. Also near invisible fatigue stress cracking and thread galling is less likely with most galvanized wires and galvanized rigging screws. These can lead to catastrophic failure.
But it is not as shiny!