kitchen floor grouting

[alan47]

Does anyone know how to brighten up kitchen floor grouting or is there a way to recolour it without having to dig it all out then regrout. thank you

[buildersmate]

There are plenty of grout cleaners around. This is one such product - widely available - shouldn't have to mail order. They are some sort of bleaching agent.
http://www.diytools.co.uk/diy/Main/p-3114-hg-g rout-cleaner-500ml.asp

[lilacben]

My grouting in the bathroom went off colour and I used Cillit Bang. the pink one. I just sprayed it on in the grouting and left it for a while, longer than they said. then used a scrubbing brush and it looks like new.