Paco wrote:
>
> Could be, but I don't think so because of the likelihood of rust,
> especially around salt water.

That's a good point, but cast iron is far more rust-resistant
than steel. I've got a couple of metal lawn chairs which have
sat outside probably for the last 60 years, and though they
show visible rust, they aren't close to being rusted through
in any places. I asked a friend of mine who is an expert on
metalworking, and he looked at the chairs and said they were
low-carbon steel which is very resistant to rust.

Also, it could be a scaler for freshwater fish. Or marine fish
that had been rinsed.