for the grease on flat surfaces use a blade, the filters can a) be put through a commercial dishwasher if not too soiled or b) be put in a heated dip tank and left to soak whilst you are cleaning the hood, as for a good chemical, the grease should be quite loose and does come off with a standard de-greaser. You could also use optimum c from chemex although this is quite pricey.
Hope this helps
Joe
Star Shine