I have a cast iron cornbread pan that is rusted over to no end. You know the ones with the corn cob molds? It's like that but with dinosaurs instead of corn cobs, neat huh? I've tried scrubbing, but there are so many little crevises that I can't even begin to get to all of the rust. Any suggestions? Perhaps something I can soak it in? Any help would be much appreciated. Many thanks.