I used many cans of Gunk. Spray it on, leave it for a while, hose it off. Repeat. For really crappy areas I used an old paint brush to rub in the Gunk before hosing off.
I also used many rags to wipe of crud. Many nights of the Gunk and rag combo, I was actually able to paint my engine last week.
Make sure you remove ALL the crap otherwise your new paint will just fall off.
I left the block to dry off for a day or 2, put about 3 coats of paint on, left that for a day or 2 and yesterday finally got everything back together and ran the engine for about an hour.
Looks great! Pictures to come soon...
Thanks
Shaun