How can you clean a glass top stove?

Ok. My husband bought a used glass top stove.. Problem is that it has thick dark rings of burn on food around all of the burners. Obviously the previous owners never cleaned it or something. I know ceramic glass cleaner is ok to use on it but what can I use to scrape off the burnt on grime? I dont know what scratch pads might be safe... maybe a glass scraper could work as well? Anything that would help would be great