We came home one day to find our b & w springer pup Jess was 'bleeding' profusely from her mouth and 'blood' was all over her white neck,ears, chest, paws. It turned out she had eaten one of OH tubes of vermillion oil paint.
It slowly faded after a few long and very wet and muddy walks and lots of vigorous brushing when dry, but only after it had attracted a few comments from concerned people. The clay acted as a pretty effective dry cleaner actually, but it wasn't instant.
I've managed to get most of it out but there is a very stubborn bit on his shoulder that aint budging. He has his first show in a couple of weeks so as long as I get it out by then
Just a few hours of walks a day should do it then.