A face curry, squirted with dawn dish soap, and sprinkled liberally with baking soda, applied vigorously to the stained areas while the hair is wet and allowed to sit for about 5 minutes should really, REALLY help. We also have an almost all white paint, and frequently get asked how we get her so white. Orvus paste is equally as good, but most people don't have it on hand. If you don't have a face curry, any softish rubber curry will work, but the face curry has tons of tiny little rubber nubs that really work into the hair. Another option would be a good stiff brush used the same way.