I'll never put used oil in my saws. My dad did for a few years on a Mac super 250 with a 32" bar. He wore the bar out and when he had to buy a new one he decided the bar cost more than the proper oil would have had he bought bar oil. He no longer did the used oil. He did however only buy summer weight bar oil and for winter use he mixed amost a qt. of Kerosene in a gal of summer bar oil. Even cut that much it seemed to have enough tac to stick to the bar.