Removing plaster stains from silver cast iron fireplace

[siobhanmccaul]

I have just had my living room ceiling skimmed and the plaster stains have not only dripped down the walls but all over the front of my brand new silver coloured cast iron fireplace. The stains have turned the metal a deep orange colour. How can I remove the stains & restore the metal?

[kbrownie]

First time ever heard such a thing, have you tried warm soapy water?
KB