First, boil a large pot of water on the stove—the pot should be big enough to fill the sink with water. Pour 1/2 cup of dish soap (it doesn't have to be Dawn, but should be a soap that cuts grease) ...

Drains are supposed to be a one-way thoroughfare, and when they operate in reverse, things can get pretty unpleasant. As annoying as a slow-draining sink or tub can be, it could be worse: Water—along ...