Here are the steps to follow:

1. Turn off the water supply to the faucet by closing the shutoff valves located under the sink.

2. Detach the pull-down sprayer from the faucet by unscrewing the coupling nut that connects it to the flexible hose. Be sure to hold onto it tightly to prevent it from falling down the drain.

3. Once the sprayer is removed, locate the aerator at the end of the spray head. It's a small mesh screen that screws onto the end of the spray head.

4. Use pliers or an adjustable wrench to carefully unscrew the aerator from the spray head. Be sure to hold onto it tightly to prevent it from falling down the drain.

5. Once the aerator is removed, inspect it for any visible debris or buildup. Use a soft-bristled toothbrush or a small brush to scrub away any dirt or mineral deposits.

6. Soak the aerator in a bowl of white vinegar for at least 30 minutes to help dissolve any stubborn buildup.

7. Rinse the aerator thoroughly with water to remove any remaining debris and vinegar.

8. Reattach the aerator to the spray head by screwing it back on. Be sure to tighten it securely, but not too tightly, to prevent any leaks.

9. Reattach the sprayer to the flexible hose by screwing the coupling nut back on.

10. Turn the water supply back on and test the flow of the water. If it's still slow or weak, repeat the cleaning process or consider replacing the aerator.

Cleaning the aerator on a pull-down faucet can help improve the flow of water and prevent clogs. It's recommended to clean the aerator every 3-4 months to ensure optimal performance.