Brush the grill with a wire brush to remove all loose dirt and debris.
Wet the pumice stone. Grasp the stone by the handle, or, if your stone doesn’t have a handle, wrap a rag around one end to make the pumice easier to grip.
Rub the dirty area of the grill with the wet pumice. Rub with a back and forth motion, using a gentle pressure. The pumice is soft and will wear away as you rub, shaping itself to the area you’re working on, including the bars of the cooking grid.
Wipe the cleaned area with a soft cloth. Rub again until you’ve removed all the grime.