Take a microwave safe bowl and fill it with water. Add a dash of vinegar. Set it in inside and turn the microwave on for 5 minutes. The water will turn to steam and the steam will soften up all the gunk. The vinegar helps to absorb the smells.
For my new cooktop :) Get rid of scorch marks on your glass top stove-Pinner says "Ok, I just tried this and it seriously did work. I did it twice on a burner that's had scorch marks for a year or more and they're gone! This really works!