I've always had trouble getting grass stains and things like that off my white mare back in germany and now off louie.
Never found a way to really get rid of them, but if you can't and really need to cover it up, baby powder covers it up alright.
And for some reason when we'd wash it off after the show the spot would always be clean too....
Never quite understood that but yeahh.
I throw my heart over the fence, and he follows it. ~Sir Louie VI- my showjumper, my best friend, my everything-iloveyou.