Ever wonder how the plumber removes the impossible clogs? The kind that do not give with plungers or chemicals? The special tool they carry is called a “snake”. A snake looks like a wire with coil at the end and is “snaked” through the drain to break up the clogs. There are several types of snakes, depending on where the clog is (sink, toilet, etc.)
Ben Franklin Plumbing has a simple explanation on it’s blog about the mechanics of a plumber’s snake: http://www.benjaminfranklinplumbingfortworth.com/wordpress/using-an-auger-for-drain-cleaning/