Ok so I cleaned my motor and painted it today here is a before and after. I covered up all the holes, degreased and used a stiff bristle brush to get everything off. It's far from perfect but this won't be a show truck. I'd say if you wanted to do the same thing and could take your engine to the car wash it would be quicker and easier.

Before

Untitled by MarcusRyan, on Flickr

After

Untitled by MarcusRyan, on Flickr