I read through the internet that professional groomer does the following for the white persian cat for shows;

1. Dish washing for the degreaser. The process was done in a fast manner and only for the affected area. Follow by quick wash.
2. For heavy stain, they use some sort of bleach agent mixed with warm water. Follow by washing.
3. Good quality shampoo then was used. Follow by washing.
4. Finally, this is important, they use white shampoo - good quality with blue based color. Rub and leave it for a while. Follow by washing.

Normally for show, the white cat was bathed once or twice a week and the grooming is consistent.

Haiyaaa how come I never read through all these thing before I buy the white cat ... anyway enjoy grooming the cats...