Pour about 1 cup of baking soda directly down the drain.
If you have a wet/dry shop vac, you have a powerful plunger alternative. how to unblock a sink without plunger
If the sink is still draining slowly (not completely blocked), boil a full kettle of water. Pour it directly down the drain in two to three stages, waiting a few seconds between each pour. The heat can melt grease, soap scum, or fat buildup. —older metal pipes are fine, but modern PVC can soften. For PVC, use very hot tap water instead. Pour about 1 cup of baking soda directly down the drain
This method uses a chemical reaction to break down organic matter like food or soap scum. 9 ways to unclog a drain without a plumber how to unblock a sink without plunger