How do I remove stains from a BBQ charcoal grill?

The only ways to control the heat on a charcoal grill is the amount of air the fire gets as well as the closeness of the meat to the charcoal. The closer the meat is, the hotter it is, so the meat will cook faster. The farther away from the coals, the cooler the heat, the slower it will cook. Most commercial grills you buy have air vents on the sides or on the cover, if it has one. If the vents are closed, not as much oxygen gets in, so the fire is not as hot. If the vents are open, the more air gets in so the fire burns hotter. I hope this is what you wanted to know.