I may be over thinking this but I'll ask it anyway.

The center section of my 8 3/4 rear is covered in caked on filth. I'm hoping that the inspection marks have been preserved under all that stuff. How should I go about cleaning off all the grime without damaging any marks that may still be there? I've never had much luck with "Gunk" degreaser and I don't want to just start wire brushing it.

Also, I know a lot of people use muratic acid to clean rusted parts. Does anyone have any tips or tricks to using it effectivly? What ratio works best? What if you don't want to dip the parts? Can you just brush it on full strength? Thanks