I have a palomino and the only products I have found to work is a brand called Luckybraids. The company has both a shampoo and whitener. I have tried them all. Most turn the hair purple or blue, Other just don't work. The shampoo does a great job on her white socks almost instantly. After I shampoo and rinse her tail I apply the spray on whitener, braid her tail and spray the braid again. By the next morning the tail is as white as can be. It removes all the yellow. The Shampoo leaves the coat soft and sleek and leaves the mane and tail easy to comb through both dry and wet. I have had my horse for 8 years and have turned her tail every color in the rainbow with products. The products from Luckybraid are the only ones I have found that work well. You can get them on line just go to Lucky Braids by Ruthann
. The price is very reasonable and the products last a while.