Any tips on cleaning the grout between floor tiles?

[Daftness]

Can anyone tell me a way of effectively cleaning the grout between floor tiles. It used to be beige now it's grey! Any product recommendations? Then is there a way of sealing the grout to stop it from happening again? 🤔

I just use fairy liquid, warm water and a toothbrush

Thanks @AubergineDream , I've done a test area and your method works quite well but is so labour intensive. We are hopefully moving later this year so I don't think I'll carry on but may be useful for our next home.

You could try something more abrasive but I wouldn't want to advise you to use something that might damage the tiles, so really depends what your tiles are. Something like the pink stuff paste should be fine, but check it's compatible with your tile first. In kitchens I find something with degreaser works better, whereas in tiled bathrooms you don't need degreaser. Fairy liquid is a mild degreaser, but if that's not working could try a stronger degreaser (lost kitchen cleaners). You could try a bigger brush, or a Sonic Scrubber if it's too labour intensive

Most not lost