Oil sticks or Oil Bars are essentially oil paint in stick form - pure pigments suspended in a linseed or safflower oil binder. The difference with conventional oil colour is that it is then mixed with a specially selected wax. This thickens the consistency of the colour. Oil sticks are sold with a dried layer of the colour encasing the non-dry colour underneath, so to begin work many artists like to use a knife to chop off the end of the stick. You can use oil sticks to draw directly on to your support to make crayon-like marks which can then be blended or worked into with oil, turpentine, or oil paint. Some artists like the effect of drawing with an oil stick into wet oil paint on a support as it creates expressive textures. You could also use it to apply watercolour-thin layers of colour by using a brush immersed in turpentine to lift colour from the stick, ready to paint with.
As with conventional oil colour the drying time is relatively slow, but can be sped up by blending the colour with drying agents such as liquin, or adding siccative to an oil based medium. A wonderfully versatile addition to any oil painter's paintbox.