To unclog a drain without the help of a plumber you will need 1/2 of a cup of baking soda and 1/2 of a cup of white vinegar. Pour the baking soda down the drain. Next, pour the vinegar down the drain. It will react with the baking soda and bubble up. Then, close the drain and wait fifteen minutes. Pour boiling hot water down the drain. Your drain should now be clear.