German Shorthaired Pointer Q&A
There is a bleaching soap at Pets mart, it is purple and smells like cherry blossom. I bathe my schnauzer/spaniel with the flea shampoo, then the normal soap, then use the bleaching shampoo last. It works!
I think the brand name is Hartz, but its Groomer's best whitening shampoo. Its very good on my westie/maltese, even gets rid of her tear stains.