I've run my searches and have read about 50 threads on engine cleaning but they are mostly for newer I6 engines with more plastic valve covers. I have the m42 with a totally exposed engine and its a pain in the ass to clean. I've tried engine degreaser and a brillo pad. While it helped a bit, its still not the silver color I want it to be. Can anyone help? I'm planning to use a foaming degreaser combined with a steel brush for my second attempt.

Try this article. It covers engine detailing in general:

http://www.bettercarcare.com/articles.php?articleId=25

Great article, Thanks. Im gunna do mine this weekend. :cool

A good cleaning with degreaser can do wonders to an engine compartment, but with an old engine it may be stained. The only way you'll know this is after you try cleaning it. If the results aren't satisfactory then you might have to re-paint the valve cover to make it look new. It's not very hard to do. Make sure you get a new valve cover gasket set for it (on my E36 M3 it was ~$25) for re-installation. The best way to prep the valve cover is to sand-blast it first. I didn't have that option when I did mine, so I just cleaned it well and painted over the top of the existing epoxy paint. I did mine well over a year ago and it has not flaked or chipped at all, and I do clean my engine bay frequently. Make sure you use high-temp engine enamel though, or you will have issues. The standard 550 degrees is sufficient.
Seth