what i do is put a catch bottle on each wheel and open up the bleeders and pour the new brake fluid in until all the old has been replaced. don't put alcohol is great for cleaning freshly hone wheel cylinders or cylinders honed in and engine block great for cleaning metal parts not so good on rubber parts like the cups in a wheel cylinder or master cylinder will cause problems, just put fresh DOT #3 and brake lines rust from the inside out, that is why you should flush every couple of years or just suck out the master and add fresh fluid.