Have black marks on your glass electric cook top after a pan was put on high heat? To remove the marks, rub the stain with a silicone spatula in small circular motions. That will loosen debris and fade the color. Make a paste with 4 tablespoon of baking soda plus a little water and spread it on the stain. Put a warm damp rag on top and let it sit for 30 minutes to soak in. After that you should be able to wipe the area clean. If the marks are still there, make the paste again but add 1 tablespoon of distilled vinegar to the 4 tablespoons of baking soda. Distilled vinegar is normally located in the pharmacy section at your grocery store. Let the mixture sit for about a minute on the black marks, use a microfiber cloth to scrub it, then wipe the area off with a wet cloth.