Rust stains on limestone terrace

[jonnyc]

Just been asked back to a job that was finished some time ago.
outside terrace is morroccon limestone aged and distressed.
there are thousands of very small pin head type rusty marks all over the terrace.
it is not evident on front terrace so we assume it has come during building works.
know that alot of work was done on railings of terrace abovewith grinder and assume this staining must be from hot filings .
tried lithofin rustex but not making much impression.
any other thoughts please

 

[Mark@Fila]

As Limestone is acid sensative, an Acid clean would damage the stone. You could try Fila PS87, diluted 1:5

Mark

 

[vitoramos39]

mix bleach with whit gepsyun and live for little wile

 

[Topshop]

Iron out would remove the rust but the area may need to be resurfaced after word.

 

[MARBLE_TONY]

Do not use bleach! keep it in your toilet! A poultice may work depends how deep it is.