After a lot of expensive products, my lovely white stones and ones with pretty patterns in them are now sparkling. I have spent the last 3 days, with an old washing up bowl filled with cheap bleach and an old washing up brush. I have lifted them in sequence (so that I remember where they go back !) and plonked them in the bleach and given them a good scrub, and a while later put them back where they belong. I am dead pleased with myself. Mrs Bouquet