Removing rust marks on sandstone?

[R.O.S.S.I]

Hi all - just wondering if anyone has any experience with or knows what would be good to use to remove some rust marks i've got on one of the paving slabs on my patio.

It doesn't look like surface rust so not sure simply power-washing will do anything! (however I am going to try!)

If it makes any difference it is Kandla Grey Indian Sandstone - bit wary of using any kind of brick acid type product. There are a few recommendations on here but nothing that directly relates to sandstone so didn't want to lob loads of vinegar or lemon juice on it and it end up wrecking it!

Any help is appreciated

 

[joeyjojo]

If you can't find any stone/concrete rust cleaner you could try oxalic acid. Be very cautious and expect to possibly make things worse though.

The following is worth reading but only mentions stuff in the USA unfortunately. https://answers.yahoo.com/question/index?qid=20061030000456AA9RegC

 

[R.O.S.S.I]

Yep http://www.pavingexpert.com/stains.htm mentions Oxalic acid. But nothing explicitly mentions what to use to treat sandstone so i'm still a bit clueless.

Was going to get a hard bristle brush and hot water and give all of the patio a scrub before power washing it away. Another thing i've seen mentioned is Muriatic acid but again, I can't see anything specific about its use on sandstone.