So I completely rebuilt my motor from bottom to top and I used all brand new good parts except the head gasket. I knew I shouldnt have got if off of ebay but I need. Anyway the car overheated and it was the head gasket. My question is I want to clean the crude off of the top of the block. What can I use to do that? Sand paper? Also when I install the new head gasket do I use the copper spray? Just let me know thanks