Smart Grooming's SUPER BLUE - the little pot of blue powder to create absolute whiteness!
Negates the yellow stains and brings brightness and white to greys. Use a tiny amount in a bucket of warm water. A little lasts a very long time.
Used as a final rinse over the whole body or just on the mane and tail.
Much like the old fashioned "blue bag" used to whiten laundry on wash day!