(in part from a post I made on Frontier Folk):
Fat is an essential ingredient in the human diet. No matter our modern prejudices, it is an efficient source of energy, it includes compounds necessary to bodily function, and just tastes good. Native people did not have as many sources of fat as we do today, since cold and hot pressing things like safflower, olives, and such was not generally practiced.
Though hickory and other nut oils were rendered by boiling, the primary sources for oils used in cooking and lubrication were animal fats. Most wild game has little fat, so the most commonly available source documented by 18th century writers was bear oil.
Rendering bear or any other animal based fat is a simple process. Chunks of the fat are heated slowly in a container, skimming any non-fat out as it heats, then straining through a basket or cloth.
Reenactors may not have a source for bear fat to use, but you can render any animal fat I can think of the same way. With things other than pork, you want to remove as much ‘non fat’ as possible before heating, and keep the temperature very low in the process. It’s especially important to get any chunks of meat off very early in the process. It makes the tallow/suet/grease less meaty tasting (I’d call it “sweeter”).
Deer, beef, even rabbit fats can be rendered for cooking; duck fat for using in confits…the list goes on. There are non-food uses as well — sheep fat for skin lubrication (lanolin), for example.
If you want to use the rendered fat for non-food use, such as tallow candles, the cleanliness and freshness is less important, but you’ll want to do the rendering outside if it’s not super fresh or has skin and meat in it.
More detailed instructions, usually specifically addressing lard rendering are available on several sites:
(I make no claims for the info on these external sites)