DON'T USE ALCHOL to flush your brake system.
all you have to do is remove as much of the old brake fluid in your master with something like a turkey baster or a syringe, i use a syringe meant for cows that a bought at farm and fleet.
then pour in DOT 5 in the master them bleed your brakes until you see the DOT 5 bleed out, easy to see because DOT 5 is purple in color. then to be safe bleed the brakes again. if there is some old fluid it will not hurt the DOT 5 fluid. it will make the DOT 5 of poorer quality.
when i convert a car over to DOT 5 i usually use 1 quart of the DOT 5 to make sure the old fluid is completely out.