My mom's house is pretty dirty from her having never cleaned the upper
levels of this small cathedral ceilinged park model. Grease from the
kitchen has been accumulating for yrs. I've tried my fave grease
cutter, 409, and it knocks off most of the crude, but a stubborn
residue remains unfazed. Almost like plaque.

What do resto kitchens --or their hired cleaning services-- use to cut
the grease in the exhaust hoods? Anyone know?

nb