How to clean blocked drainage lines Blocking drain lines is a really annoying thing. Here we are going to say how to clean clogged lines without removing pipes or make your hands dirty. Before start, get rid of the excess of water present in the sink. Pour half a glass of sodium citrate and half a glass of baking soda into the clogged drain line. Pour a gentle flow of 1 glass of warm water. It will react inside and create a foam. This will clean all the food particles, oil, grease in it. After 10 minutes, make a larger hot water flow to rinse everything away. See! how it is wonderful.