ᐅ Removing plaster residue from sandstone

Hello everyone!

How can hard, dry plaster residue be removed from sandstone? These are sandstone blocks of a garden wall.

By the way, I'm struggling to come up with more lines (to reach 200 characters), even though I believe I have already asked my fairly straightforward question. Thank you very much!

Regards,
Mike

Without having tried it myself, I would suggest using a stiff brush. In the worst case, a softer wire brush.

Without damaging the surface, probably not at all.

Chisel off large chunks, sandstone may come away with it.
Possibly use a wire brush.

If you have time, frost may cause it to separate on its own.

Ok, thank you very much for the responses so far. Is there maybe a milder option? Acetone?

Not tried. Sandstone is very soft. I would not trust chemical solvents.