Wash away any remaining leaves, dirt, and gravel with a water hose.
Apply an oxygenated cleaner in powdered form to the stained area, and let the cleaner soak for 15 to 20 minutes.
Wet the bristles of a scrub brush, and use it to scrub the affected areas.
Rinse the cement thoroughly. If you have a pressure washer, it will be most effective at removing all traces of leaf stains. However, if you don't have a pressure washer, use a spray nozzle on your water hose.
Add more cleaner and scrub again, followed by another rinse, if necessary.