getting the yellow out

hey everyone!

I really think I should have named my colt pig pen, because he is FILTHY. I spent two hours the other day trying to get the yellow out of his tail with the blue coloured green spot cowboy magic shampoo. It got most of the yellow out but not all of it!! I put it up in a tail bag, and I think I'm going to try again to get it white this week.

Does anyone have a secret recipie or product they use that's really effective? I'm at my wits end!