Actually, cooking oil, assuming it wasn't used cooking oil, shouldn't do a whole lot of damage. As it is non-conductive, it would short anything out like water or most other liquids would. If it got into the hard drive that would probably do permanent damage, and if it got between the layers of the LCD would be very hard to fix without replacing the entire LCD, but other wise the rest of it would just need to be fully dissembled and cleaned.
Doesn't shorting stuff out do some major damage?
cooking oil is non conductive, meaning it wont short out electrical components. look up oil cooled computers