Cleaning engine blocks and cylinder heads is just as important as the machining operations. There’s no single cleaning process that is right for every application because aluminum and cast iron are very different metals. Because of this, rust control and prevention are major concerns when cleaning and preserving cast iron blocks and heads. All of these external and internal surface contaminants have to be removed by the cleaning process. Machined parts also require some type of post-cleaning to remove oils, metal chips and honing residue.