At home, a crock pot will suffice, as it can simmer at a low and steady temperature for several hours uninterrupted. In the backwoods however, rending over a fire can be a lot trickier, though it is worth the trouble. Ideally, to render fat, you'll cut up animal fat into one-inch cubes, removing all visible meat, veins, and non-fatty tissue. You just want animal's fat. Drop these into a pot with a few inches of water in the bottom.