Bob,
Great find......I'll second the atf as it has cleaning agents....plus it's a lot cheaper than kroil.......I'v used a mixture of atf and diesel to thin it out some so it will get down the cylinder walls........as well as removing all the plugs when trying to turn it over by hand....well more like rocking it as you don't want a ring to break or scrape a large amount of rust at one time as it can damage the cylinder walls.
Mike