Turn off the faucet
Unscrew the aerator from the faucet tip
Separate the aerator parts
Rinse off loose debris
Soak the parts in vinegar for 15 to 30 minutes
Scrub the screen and parts with a small brush or toothbrush
Rinse all parts thoroughly
Reassemble the aerator
Screw it back onto the faucet
Turn on the water and check the flow