I'm in the process of having my very dark brunette hair bleached blonde, with the intention of eventually going silver. I got a full head of highlights a couple of weeks ago and was immediately told by my stylist to invest in a good, "violet toning" shampoo, to neutralise any brassiness in my hair (and trust me, there was lots!). Doing a basic search for violet toning shampoo introduced me to Fudge's 'Clean Blonde', and after reading and watching rave reviews of the product, I ordered myself a bottle. I can't tell you how much I adore this product. My lightest highlights are now a perfect silver colour, and my darker ones are a lovely golden blonde - and I've only used it twice! I can't wait to see what it'll do to my hair once I've gone even lighter! I'm also amazed at how soft and manageable it's left my hair - it doesn't even feel like it's been bleached :)
A little bit of advice: I would definitely recommend washing your hair once with your regular shampoo before you apply this - I found it easier to get a lather with this product when applied to really clean hair. A lot of reviews also recommend wearing gloves to apply, as it can stain your hands and nails. I can't vouch that this is accurate, but I've been using gloves just in case. As a side note, it smells absolutely divine and is particularly fun to rinse off when you're having a bubble bath.. it turned my bath water bright purple!