My ce2 was so gunked up when I tried to clean it today that a dry burn toasted it the second the coil started getting red. Rip
if it's really gunked, you can't just blast on the battery button until the coil gets red. 5 seconds at at time....tops. Then wait a few seconds... and then keep repeating until the gunk is gone. You'll see the smoke pouring off it, even if the coil doesn't get red.