On 28/10/2020 11:15, 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?


Remove and replace the tiles.

Bill