There are several oils that can be extracted from nuts and seeds. The basic technique is to crush the nuts and/or seeds and boil in water. The oil will rise to the top and can be skimmed off. If you use a tall narrow container it's easier to skim without getting too much water. The best nuts to use are Beech, Black Walnut, Butternut, and Hickory Nuts (this is considered the best). As for seeds, Sunflower (particularly the black oil type), peanuts, rapeseed/canola, flax. The problem with the smaller seeds is that it takes so many to amount much oil. Keep oils cool and dark, don't use them if they smell or taste rancid.