most people put them in the sink filled with warm soapy water, I like to use the sink hose and put the shampoo on straight. You can use just dawn or you can use a dog shampoo, whitening works best for whites. But nothing with tea tree oils or that is tearless those are bad for them. I just gave my polish a bath in fact. After rinsing the soap off rinse him in water with a little apple cider vinegar, it will cut through any remaining soap and moisturize the feathers. I prefer to blowdry my chickens(on semi-warm, not too hot) after the bath but many people will just put them in a pen with shavings and a heat lamp to dry off. Just make sure they stay warm while they are wet. and don't get water up their nose or soap in their eyes.