I have been using a mix of diesel varisol and gunk to remove the heavy grease from parts and frames, but it does leave an oily film that has to be removed if you are going to paint, ie engine blocks but then in most cases you have to wirebrush the casting to remove the rust film any wayand wipe down with acohol or laquire thinner before painting, on painted parts i just leave the oil film for storage, to stop the surface rust from forming.
