Making candy or caramel can easily result in some burned sugar in the bottom of your pan. Cleaning burned caramel from a pan can be a bit of a challenge.
Cleaning burnt on food off of glass cookware, such as Pyrex baking dishes, does require products that will clean but not scratch. This is a page about cleaning burnt food on glass cookware.
If you have any burnt pans: instead of scrubbing them, simply fill pans that are burnt on the stove with boiling hot water and simply put a little soap powder in the pan. Boil gently for about 10 minutes then rinse out thoroughly before use.