In order to temporarily colour your hair white, you will need to apply a spray-on hair colour. Spray-on hair colour is easy to apply and easy to remove, as it merely coats the hair with a washable paint, as opposed to permanent whitening methods -- like hydrogen peroxide -- that completely strip the hair of pigmentation. Most spray-on hair colour products come in aerosol-type containers and can be purchased relatively cheaply at costume shops.
Place a towel around your shoulders to keep the spray-on hair paint from ruining your clothes.
Shake the can of spray-on hair colour.
Close your eyes and spray your hair with the white hair colour. For full coverage, you will need to spray your roots, too. Make sure the can is between 30 and 46 cm (12 and 18 inches) away from your head as you spray.
Check the coverage of your hair using a mirror.
Close your eyes and spray your hair again if you notice patches of your real hair colour showing through.
Wipe excess paint off your face and forehead with a damp towel and gentle hand soap.
You can easily rinse these types of hair-dye sprays out of your hair using normal shampoo and conditioner. If you want a more natural white look, avoid spray-on hair colour with glitter in it. Make sure to apply the hair colour only after your hair is completely dry.
Avoid getting spray-on paint in your eyes. Do not use spray-on hair colour on permed or dyed hair.