My roommate left aluminum foil on the warm cooktop. He was able to remove some of it, but sonme fused to the cooktop. I've tried the following to remove it:

1) vinegar, baking soda, and cooktop scrubber
2) hydrocholric acid, in the form of toilet bowl cleaner. I used two different brands (The Works and Lysol).

Neither of these options worked.

Anoher option I've read about is applying muriatic acid. I'm hesitant to do that because it's got a lot of fumes.

Any suggestions?