I had a recent guest who arrived with blond hair, but left with Navy Blue hair. I was a little angry when I found navy blue stains on a pillow case and the sheets, along with blue splashes on a tan Venetian Plaster bathroom wall. I mean, dammitt. I'm going to have to replace some very expensive sheets, and I'm going to have to repaint an entire bathroom. Have you ever done a tedious Venetian Plaster application in a bathroom? You can't just touch that up. And the product is around $80 a gallon.
I thought I'd attempt the impossible, and treated the stained linens with bleach before tossing them in the washer. Wow. Imagine that. The stains came right out. But the blue stains on the bathroom wall required the judicious application of bleach with a cue-tip. I probably had to daub bleach on those spots three times before they disappeared.
Have you got any bleach? I used the Clorox "Splash-less" variety. It didn't run down the wall as fast as regular bleach would have. I think I held a paper towel to the wall below the area I was treating to keep it from dripping all over.