If you have time, perhaps have a go yourself. Can you put up a picy of the engine bay, then we can give you tips. Is it really filthy? When I'm grooming engine bays, I use lots of very long handles fine paint brushes for the rubber piping, and gently brush the product on. A few bigger brushes, that are slightly damp to get off dust. Can give you a few more tips once pics if you like.