[Rich in Vancouver]

What products and methods have members used to good effect to remove the grime that accumulates on the underside of the bonnet and the other painted bits in the engine compartment? This black deposit is baked on and I would like to clean it off without ruining the paint, and without spending day upon day scrubbing if possible. I don't have access to a steam cleaner and would prefer not to use Gunk spray or similar as I don't have a suitable run-off area for the disgusting mess that cleaner creates.
When I did the front compartment (Frunk? Froot?) on my MGF I used cut polish but not having an engine there it wasn't as bad as the ZT.
Any ideas appreciated!