Brush away any dirt or gunk from the posts, because you'll need to create as clean and solid connection as you can. First, ...

Instead, place the remaining black clamp on a bare metal part of the dead battery car, like a bolt. Turn the good car’s engine on and let it idle for 2 to 3 minutes so the dead battery car can ...

Disconnect the black clamp from the previously dead car, which should be attached to a bare metal area of the chassis (not the battery's negative terminal). Then remove the red clamp attached to ...