Thermal Cleaning...Check it out.

I recently dropped off a /6 short block at a local one man shop to get bored and checked out. When I asked about "boiling out" the block he said he cleans with heat. He showed me his oven and I asked what temp and the answer was 700*. After baking, he puts it into a shot blaster with a rotating table (like a microwave). I looked at a 1956 Oldsmobile V-8 he was assembling and the bare castings looked good. He said all the bad stuff turns to powder, even rust. He's backed up with work right now but I'll take pics when mine is done.