Family friends from South African moved to Australia (from Canada) and left me behind with two absolutely beautiful cast bronze skillets. To pre-empt your question, I am 99.9% sure that it is indeed bronze, not iron or copper. They're bloody heavy, I'm a very large guy but I wouldn't want to hold the larger one in the air for any length of time, let alone above my shoulders. The general shine and design (two side lips, opposing bump for grip) is similar to the one shown here:
Except that mine have wooden handles that I've figured out how to remove (they're on a steel rod).
I have been cooking with these and have absolutely loved them, but I was starting to wonder whether things were sticking more over time. More importantly, they were loosing their shine and gaining discolourations. So I went looking and started to wonder about seasoning and cleaning. Especially since I suspect my friends inherited them and kept them as decorative pieces, so I'm not sure when they were last used.
What it comes down to is that there is absolutely nothing I can find about the proper care, cleaning or seasoning of cast bronze beyond one pitiful link (http://www.ehow.com/how_4663344_stain...) that doesn't even to be talking about the same kind of item. So, do they require seasoning? Will soap or soaking hurt (found conflicting accounts)? Should I use lemons/vinegar/salt/baking soda? All advice is welcome.
In summary, I'm at a loss, there seem to be no skillets like this on the Internet and few in the world, and I'm hoping that one of you has the answer.