Claening a Tin Sided V8-60

[$um Fun]

I have tin sided flathead with over 40 years of caked on sludge and managed to remove over two coffee cans of sludge and want to get the block cleaned. I have been told that you don't want to hot tank the block with the tin sides and is like putting aluminum or brass in a hot tank.

Any ideas or methods that others have used to clean tin sided blocks would be helpful. This block is really filthy from not changing the oil.