Cooking grease on painted walls?

I just spilled cooking grease on my newly painted walls, paint is less than one month old. Luckily I have the exact paint but how do I paint over the surface? Should I sand the area down or just paint on top of the stains. HelpCooking grease on painted walls?
your best bet at this point would be to wash the walls with a good detergent..allow to dry completely, then go to the hardware store and pick up a can of KILZ paint primer..this will seal any grease that is left...Kilz will dry quickly then you can repaint your original colorCooking grease on painted walls?
you'll have to shellac the surface or the grease will bleed thru the new coat of paint