When you notice a nasty clog, your best bet is to fill a pan with hot water. Heat it up on the stove or use the tap, but don’t let the water get to boiling point. Pour it down the drain and let it sit for a few minutes to see if it loosens the clog. You’ll know if your efforts were successful if you see the water start to drain. Then, give the toilet a flush or two. In many cases, the hot water is enough to break up whatever is causing the backup.