My friend has a JRT that is 95% white, and he used that special whitener shampoo, up until all the doggies at the park started teasing him about his beauty parlor looks and using a froo-froo conditioner. Some dogs are just meant to go natural!

But, other than the social stigma (which bothered the owner rather than the pup), the shampoo worked great, and they did keep using it after all!