copper sink green If you have a copper sink that has turned green, it may be time to clean it. Copper is a toxic material and can cause health problems if it is ingested. To clean the copper sink, first remove any dirt and debris that has built up on the surface. Next, use a plunger to suction onto the bottom of the sink and pull until all of the water has been drained out. Finally, use a mild soap solution to clean the entire surface of the sink.