Currently working on a sandstone floor installation that has been abused by builders.
Worst I have seen (and I have seen many)
We have managed to remove everything but mortar/cement spots from the tiles.
Is Hydrofluoric the only answer to this?
We have tried Hydrochloric, Phosphoric & Nitric (qualifying possible damage with customer) these wont shift it.
Anyone any experience of this? Can you recommend a supplier? We only have 10% stuff which aint touching it.