A plunger is the most versatile tool for slow-draining sinks. It creates enough suction to dislodge minor clogs caused by hair, soap, or debris without requiring harsh chemicals. We use them often because they're simple, effective, and won't damage pipes. For best results, ensure the sink overflow hole is covered or sealed, and use short, controlled plunges to create pressure. It's a quick fix for many common issues and saves you from unnecessary service calls for minor blockages.