Removing residue from my stone and brick fireplace

[PHILTAL1]

I have removed all plaster from my fireplace but layers of residue have been left what is best way to remove this without damaging original stonework

[tabbypurr]

On bricks you can use HCl aka brick acid - but not on stone! Tell us what the residue is.

NT

[John Rumm]

Those stones could be limestone or something else sedimentary. So HCL may be too harsh. I think I would start with some soapy water and a stuff bristle brush. Work up to a wire brush if necessary.

[harry]

Sand blaster. Possibly pressure washer and/or wire brush in angle grinder