Does anyone know what to use and how to clean
plaster ceilings(bumpy and white). My studio kitchen doesn't have a good ventilation duct and the salmon oils from the grill are definitely making the ceiling dirty and grundgy. Any hints besides stop cooking?

Thanks!

Inviting your mother over for dinner is probably the best solution.
I have found that the safest product to use that does a reasonably decent job is 409
(Simple Green is as good but more expensive).
It really does a good job with automotive grease and oil and those are the two items that you will have on your ceiling.
You should also consider a ventless kitchen hood that you can take with you whenever you do relocate.