Comments on the Star K Response -
There are several "sn'iffim l'hokeil"
1. BBQ's are rarely used for Hameitz B'ayyin
2. SCO's - while not as hot as a blowtorch - have a longer cycle
3. Eino ben yomo
SCO should be sufficient to Kasher BBQ
I would suggest using EZ-off to pogeim the ta'am first.
Why am I Meikel?
I believe what my eyes see! After a SCO cycle, there remains nothing but dust. While torches and coals are potentially dangerous.
Consider that - just as EG several modern Poskim have allowed Steel Wool as the equivalent of n'itzah b'karka for cleaning shamnunis off of knives - so too SCO's seem to be a modern technological equivalent to Libbun Gamur.