On 30/10/2020 10:47, Dave Plowman (News) wrote:
In article ,
wrote:
On Wednesday, 28 October 2020 11:16:07 UTC, Dave Plowman (News) wrote:
Was grouting some new tiles, using the combined waterproof
adhesive/grout, and got called away before finishing off. The actual
grouting is fine - but a lot of residue on the tile faces, now rock
hard. Tiles are ceramic and matt finish. Any tips on the easiest way
to remove the residue?

acid

What would that do to the actual grouting which is fine?


Harpic ?. Contains dilute HCL and is sticky enough to
adhere to the tiles rather than running off too quickly.