Tips, How to Clear a Clogged Waste Pipe: You can't go past the good old fashion plunger to force the block from the plumbing pipe. It's the force of the push that forces air through the pipe to clear the clog. Before plunging cover the overflow with a damp cloth to ensure a drain seal and force the air out through the drain blockage. If you have a double kitchen sink make sure you block off the second drain to ensure good pressure. Try this a few times before you throw your hands in the air. Many home have reported this to be one of the most successful methods.