Andrew added: "Watch as it bubbles and fizzes. This will loosen more mould spores in the grout and allow you to remove the mould more easily." Use an old toothbrush and a clean cloth to wipe away ...

There are several ways to remove the white staining of efflorescence. A stiff brush or broom can remove a lot of the white stuff. If that doesn’t do the trick, you can wash it away with acid.