Let the stovetop cool completely.
Add just enough water to 4 tablespoons of baking soda to make a thick paste. Spread a quarter-sized amount of the baking soda paste to the burnt residue.
Scrub the baking soda paste into the burnt residue with a nonscratch scrubbing pad. Scrub until the burnt residue is gone or until you cannot remove any more of it.
Hold a razor to the surface of the stovetop at a 30-degree angle. Slide the razor over the area until the burnt residue is gone. Then, scrub the area with the nonscratch scrubbing pad.
Rinse the area with water, and dry it completely with a clean cloth.