Shimmer Lights is the iconic brand of anti-yellowing shampoos. So iconic that Clairol doesn't even promote it on their website! (That's how much Clairol hates gray hair!)
This dark purple Clairol classic is your grandmother's gray hair shampoo and YES you should use it too! But don't be like granny and use it every day and become a "Blue Hair". Use it only occasionally to get rid of any yellow tinge or brassiness. And be careful, this stuff stains your shower grout blue - permanently!