I generally use a sharpened putty knife then a razor blade to clean up the mating surface. Then I clean up all the grease and oil with lacquer thinner. The block being cast iron is pretty tough as long as you use reasonable care. And if you want to dress it up a bit, now is the time to clean up the sides and give it a quick spray paint job, either the original black or something lighter so you can see dirt and leaks before they get real bad. Mike W.