Thanks, I went downstairs and gave the denatured alcohol a try, it seems like it was an improvement over water.

The dent is pretty deep and, I suspect that it has been there a long time. I've been thinking that it probably won't come out immediately,
so I've been steaming and then waiting a day or so, I've got plenty of other stuff to do, and coming back to it with more steaming. Is this ok?

Fred