I have a black gas stovetop (i.e. not glass), and I've gone from hades and back trying to get that sucker clean -- mainly the burner pans and grates. Tried ammonia, vinegar, magic eraser, anything from borderline corrosive to all natural, soaking all night, yadda yadda. I also found that Barkeepers Friend (the liquid version) finally made a dent. I am a little cautious about what it will do to the finish over metal, so I make sure to use a damp sponge to rub it in.