The block needs to be fully disassembled prior to any machining. This can be done at home, or by the machine shop. After a quick inspection for obvious damage, the first step is to thoroughly clean the block. If the block is obviously very rusty, the shop may place it in a shot-blast cabinet. This machine uses steel balls (instead of sand) to strip away corrosion and grime. The shop may opt to treat the block to a hot bath in a tank containing a caustic solution heated to 200 degrees Fahrenheit. This serves to clean away all of the grease and grime in addition to the rust, and makes inspecting for cracks and flaws much easier. The most-common procedure is the "jet-clean" system shown in the photo. It uses hot water and a cleaning solution sprayed on the block, while it revolves around on a turntable. During the rebuild procedure the block will usually be cleaned, at least twice, in the "jet wash" machine.