I use model masters paint and a brush to do my tracks. If the tracks are the rubber band type (Tamiya) I will paint them before I join them together. I use model masters rust with a little flat black mixed and paint the entire track insdie and out. After they are dried, I dry brush model masters steel to high light the the tracks. I do the cleats on the inside of the tracks as well as the outside metal portions. If the tracks have rubber pads, I will paint them with a flat black with a follow up of grey as a dry brushing. After all this is completely dry I will give the entire track a wash of Rust-All and black wash. I give it as many coats of this wash as it needs till I am satisfied with the look. Depending on the type of location the unit that uses this particluar tank will tell me if I will use a heavy mud or dusty finish. This will be done when the tracks are installed on the tank. If the tracks are indi links I will assemble them and paint them after I have installed them on the tank.