I didn't have any machine shops nearby or within my price range during my first engine rebuild so I grabbed some magnaflux spray on crack finder for the head. It's an AMC 4.0 I6 from a 96 grand cherokee if that matters. The good news is no cracks and the head using feeler gauges and a straight edge is not warped. The bad news is I don't know how to clean all this magnaflux developer dust off and I don't want to fuck up the surfaces. I've brushed, air sprayed and wiped but this shit's in there good. Any ideas?