I have a white mohair teddy that really looks a bit grey. I have washed teddy bears and soft toys in the washing machine and they have always come up good - well nearly always! But I do not know how to clean mohair. I am not sure if it would just 'matt' if it is washed.
i washed mine in the sink with my own shampoo and conditioner and it worked really well though i was terrieifed as i did it. Obviously air dry - don't tumble!!