Dick Van Dyke, who played a chimney sweep in "Mary Poppins," and who made that profession better known, was born on this day. Whereas he clowned around about being a "sweep," it's serious business. Problems often stem from burning wood that is too "fresh" -- meaning it has not been dried sufficiently. Reducing moisture from a fresh 50 percent to a correct 20 percent or 25 percent takes from six to 12 months. And, burning moist wood uses a lot of heat to boil the water and sap away. Lower temperature fires produce creosote residue that builds up inside the flue and chimney walls. This residue is also flammable and can ignite, causing a chimney fire and filling your room with smoke. This is where the chimney sweep comes in -- to clean it. Intervals between cleaning can be extended by choosing the right woods, which mostly means burning seasoned, dry wood instead of freshly cut "wet" firewood.