The fascinating question of cleaning black grout

[Planesmistakenforstars]

Hold on tight for this exciting thread!

I have black/charcoal grey grout on my bathroom floor. Over the years it has turned into a dirty looking lighter grey, and no matter how much I clean it, it still looks grotty. DP thinks it's a build up of limescale (we live in a very hard water area.) I've tried scrubbing it with vinegar & lemon juice, and I've recently got a steam cleaner and used the small brush on that, but it's made no difference. Does anyone have suggestions for how to make it look clean?

Astonish mould and mildew blaster from Poundland has worked wonders on my grout

Hang on I've just realised the colour has got lighter, not darker.... Scratch my original suggestion!

Thanks, it might still be worth a try though!