I still haven't found something that gets rid of green knees
Plus the fact that he suffered from mud fever due to too many washes etc. I don't like using anything strong
I have heard good things about cowboy magic green stain remover, although I am getting pretty good results atm using baby shampoo and fairy liquid on his tail
I use the following on my lot: anti dandruff shampoo for normal every day washing, For stained white tails I use biological washing liquid, wrap in cling film and leave for a while then shampoo off (only on the tail below the dock). I also do this with grey feathers but make sure it doesn't get on the skin, just the hair. I also use a purple shampoo which I actually use for my own blonde hair on my piebald and my grey. Its called Provoke Touch of Silver Shine Weekly Treatment Shampoo and you can buy it online. I think it probably works out cheaper than the special horse shampoos if you find a good deal. It brings the white and the black up really nicely I leave it on for about 5 mins (any longer and theyll have a granny rinse!). Its not the most lathery though so I usually use it after shampooing with the anti dandruff stuff.
Oh and there's this blue stuff I use but I can't remember the name. It's like that laundry blue you used to be able to get and you just add a bit to the final rinse. I usually put a drop or two of tea tree oil in the water as well to keep their skin in good nick.
I also couldn't cope without Canter mane and tail spray to keep them tangle free.