My mare's mane/tail is multi-colored. One of the predominant colors of her tail is white. The middle to the ends is not as white as it should be...which is blinding white as it is at the top. I have washed it w cowboy magic and heavily diluted liquid tide. It helped, but it didn't completely remove all "dirt stain". Anybody know of a good product that won't also lighten the other colors on her tail?
Have you looked into Ecolicious Equestrian's "Blinded by the White"? It's a green, chemical-free product that you can use on the entire horse -- not just it's tail. My Appy is looking the same way (her tail is so white on the top and so near-black at the bottom) and I'm going to use it! Good luck! :)
I have a VERY light palomino, basically white gelding, so I know how you feel. Once the night before a show, he rolled in manure in his stall and it was ALL OVER his belly! ON the same day, he started to grow out his winter coat, so he was a mess. At least it was only an open show. I use shapley's show touch-up- it comes in alot of colors. Also, baby powder. It makes them smell good, too :) Quic-silver is good shampoo. I use a tail bag all spring and winter, and rainy days in fall and summer.
A girlfriend of mine is Ecolicious and she gets me to help her test and demo her products all the time. Not only do they work well, smell amazing but they're incredibly gentle and natural on your horse. Man, how's that for a shameless plug? Lmao! Truly, I even enjoy using the stuff in my dog grooming salon.