When you rinse him use some of that liquid oxy clean detergent (the stain fighter) I usually found it at Wal-Mart. Let it sit in his hair for 5-10 min then rinse out...Make sure you only add the oxy clean when the hair is wet b.c this stuff can make the skin a little extra sensitive, but I never had too big of an issue with that.
In the laundry department at walmart near the woollite you will find a small bottle of liquid bluing. It will make it white be careful and don't use to much because it can turn it blue just as easy.
I did see that Sullivans carry it as well but I am sure walmart is cheaper.
Bright lights or some other type of whitening shampoo, you can also go to walmart and get some of that shampoo old ladies use to make their white hair shine it works well and maybe cheaper than Bright Lights or the Kirk Stierwalt whitening shampoo. We have herfords and thats what we use to keep the white clean
i had a steer once with white hips and back legs.....i scrubbed the stained areas with Joy dish soap daily, and about a week before shows i would scrub the stained spots with a whitening shampoo daily. it takes alot of elbow grease but you can successfully keep them white and the daily shampooing wasnt harsh on his hair at all, didnt dry it out or anything.
Seven up..as in the soda helps. Oxyclean laundry spray, or if horrible make a paste out of the powder by wetting the area then rub powder in leave for good long while, overnight fine then rinse out. Or Sullivan stain buster actually works too