Detailing Valve covers on my 328 ???

What product do you reccomend to clean the valve covers on my 328 and other engine components , I am looking for a winter project !!! Also what type of finish is on the rocker panels [below the doors ] mine are covered in a rough undercoating ?? Is there a smooth plastic under the undercoating ?? Thanks for the info , and if you could suggest a product to clean off the undercoating if its not supposed to be there Thanks Elliot [email protected]