park next to fire hose reel at your work
-after engine cools down (but is not cold) pop bonnet
-liberaly spray engine bay with numerous tins of cheap degreaser from supacheap
-let sit for 5-10 minutes
-hose out with fire hose, being careful not to soak sensitive stuff too much (like the air cleaner or alternator
-allow water to drain away
-start engine to shake off water and boil off any water pooling on engine
if approached by security or other official persons about improper use of the fire hose, say that you thought the odour from the degreaser was petrol and hosed out engine bay to prevent a fire