I recently cleaned my engine bay using the instructions found on this website:
www.1fastrex.com (go into the "detailing" section)
Came out REALLY nice... I'd never even seen the engine code stamped on the block before, it was so dirty. Took about 4 hours to do the first time (I'm a perfectionist), but only about half an hour every time after that (if you do it regularly).
Anyways, I had the same problem with the battery acid, just bought a can of that battery acid cleaner stuff, worked pretty well.