T.N.
I've used the "Barkeeper's Friend," which is similar to Comet or Ajax cleanser and in a similar looking container, but it's not as full of harsh chemicals. It has some gold on the outside of the container and I got mine at Walmart in the cleaning product aisle. I've successfully used it clean my glass top stove. I just used that and scrubbed with a washcloth. You may need to do it a few times and use a lot of it to get all of the grime off.
T.