An hourly rate would be best as each kitchen varies so much. If it's not something you have done before perhaps it might be worth subbing it out. If you do decide to go for it think about the following:
- When can you access it and when does it have to be back operational (If it's a night shift you have 'lost' the following day!)
Clarify who will empty and refill the deep fat friers.
If you are not cleaning the extract ductwork qualify by saying..... "clean as far as armsreach"
Remember any caustic based cleaning agent will damage aluminium.
If you are going to use a dip tank for any really carbonised bits and pieces and you are using caustic soda be very careful. Premix gradually in a plastic bucket then add to tank. CAUSTIC SODA AND WATER REACT EXTREMELY STRONGLY
Full PPE including long sleeve gauntlets / visor / wellies/ rubber apron etc
It might sound like overkill but I remember sitting on the edge of a DFF many years ago with all my safety kit on during a tea break and my overalls got slightly damp. By the time it started itching I was burnt through my bum cheek to the bone. But I have never forgotten it.