Turn off the burners, and let the glass cooktop cool before removing burnt-on foil. It can take up to an hour before the top is cool enough to touch.
Hold the razor scraper against the glass near the foil. Push the edge of the blade underneath the foil. Keep applying pressure against the foil until it is all scraped off. If the foil tears, clean off the blade and repeat the process until all the foil is removed.
Squirt some of the cream cleaner onto the cooktop. Wet a sponge in hot water, and clean the stovetop.
Rinse the sponge as often as necessary to remove all the cleaner and debris from the cooktop. Use a paper towel to dry and buff the glass surface to a shine.