Lard, tallow, or sweet oil, were all used as lubricants and rust preventatives. I only use that method, water, tow, and grease or oil. Don't use bacon fat, as there is salt in it.
Lard is rendered pork fat, and tallow is rendered beef or sheep fat.
I like to mix two parts of warm liquid fat or oil (or even shortening), with one part melted beeswax, to make a grease for mocs, and for guns. It also works as lip balm, skin protectant against biting winter wind, and one can fashion an emergency candle out of it. Further, it's non toxic, when your youngin or grand youngin gets into it! Finally, it's dang cheap [Scottish heritage coming through there]
LD