I would clean it by soaking it in lacquer thinner for a few days, and then blow it out with compressed air (low pressure). If it comes clean with the first soaking, great. If not, then put it back into the thinner, and let it soak more, until the insides are clean. Then pressure test it with low pressure for leaks. You can extend the in and out lines with rubber hose and pinch off one hose. Lightly pressure the container, and put it into a pail of water. If you see bubbles, then it is defective. If not, then it is good to go back into the car.