My FReind,there are no least important areas.
You are right but I meant the curb or the places hidden from direct line of sight. It is better to "test" small areas like those before irreparably damaging the actual wall.
Comprende?
They would probably be able to get a sample of the granite from a tombstone company to ‘practice’ on, providing they can determine what kind of oil (cooking? it looks clear to me from the pics) was used, and what might remove it from the engraved portion of the granite, if that is even possible.
Unfortunately, I think the whole wall panels would have to be replaced. :*(