naw yeah I did that, and I've figured out that glass stove top cleaner is actually great at getting water spots etc off...I'm pretty sure that the glass (for whatever reason I really don't know I just guess it may be algae) is actually scarred on the inside, like pock marked with dimples that algae likes to grow in, then you have to scrub like an angry demon to get it of during maintenance, its really hard to see, but it annoys me a wee. It could also be acid etching...idk what they were doing with this thing before i found it lol.