Can't get plaster marks off front of fire

[VexedofVirginiaWater]

I have just had some plastering and decorating done in my living room. The decorators were great - covered everything I hadn't been able to remove (I did move most stuff) but the plasterers, although they dust-sheeted the large pieces of furniture, didn't cover the fire or fireplace. I am kicking myself because I could have moved the fire (it is electric) but I suppose I think of it as a fixture, like the fireplace, so I didn't.

Anyway some plaster must have fallen onto the fire - it is a black metal rough surface - and I can't get it off. I have tried soap and water - and multi-surface polish on a small section - but no luck. I am going to try again scrubbing really hard with a different brush, but what a mess!

Has anyone got any ideas or suggestions please? (Thank you)

What about that stuff in the yellow tub, Elbow grease? I would try that then wash off well and leave to dry. I would then put some olive oil all over a very very slightly damp cloth and rub in to the black grain to. Kind of bring the blackness back through and make it look even (I have to do this on my black grainy bathroom radiators as they always look grey and water marked)

Ah thanks - will see if I can get some (think I might have some pink paste in a tub not sure) - and good call about the olive oil, I wouldn't have thought of that!