Justine, one doesn't normally clean the Whites for the show, but one must KEEP the Whites white for showing. Once they're stained, they're very hard to get clean for a show. If you have farm birds like mine? I don't care. But, if showing is your intention, you've got to raise them entirely different. Cannot even use roosts where the bird above will poop on the bird below.
Raising, conditioning and showing White birds is it's own special world. PITA
I've got a White Rock pullet I'd love to put in the Fall Poultry Fest as I think she is a rare enough bird to bother with showing. Alas, I'll not enter a pullet that hasn't laid her first egg, for a pullet will never look better than the day she lays her first egg.
These pullets I have are not going to make lay soon enough. Such is life. The only reason I'd show her is just to see and hear the feedback from others and from the judge. Make sure I've not lost me sight completely to horrendous near sightedness and cataracts that plague me these days. Or, just admit to some level of barn blindness.
I read in an old book about a fellow that had award winning whites and he let them dust bath in flour.
