Some people cover their grey or white hair as they age, and others make their hair that colour because they like the look. The process involves stripping your hair of its natural pigment and neutralising the basic pigment that's left behind, also known as the "brassy" yellow or orange colour. You'll always need to bleach your hair and strip it of the existing pigment before you can tone it to the shade of white, silver or grey that you want.
Wrap a towel around your neck and shoulders, and slip on your gloves. In a large plastic bowl, using your dye brush, mix the bleach and activator together in equal parts. Mix in the powder until it becomes pasty.
Part out sections of your hair vertically with the pointy end of the dye brush, and start applying the bleach at the top of your hair first. Brush the bleach on at your roots with the dye brush to make sure you apply it evenly, and work it out to the ends.
Wrap your hair up with plastic wrap, covering it completely. Blow some warm air on it with your hair dryer; make sure your whole head gets the warm air in even amounts for 15 minutes.
Unwrap your hair, and rinse the bleach out thoroughly. You'll need to wait at least one or two days before before you bleach it again. Unless your hair's already a light blond, you may need to repeat the bleaching process three times before you get it to white. If you're doing this without the lightening powder, and you're using a toner to neutralise the yellow, don't bring it all the way to white with the bleach. You'll need to bleach it to a light yellow, and then apply the toner to make it white.
Apply a deep conditioning and repairing treatment to your hair after each bleaching, and use it twice a week after that until your hair feels healthy and not so brittle. Bleach is extremely damaging, and you'll need to be gentle with it right after the bleaching.
Keep your hair from going a brassy colour by mixing some semi-permanent purple hair dye in your daily conditioner for when you wash your hair. The quick hint of purple neutralises the yellow and brings your hair back to white. Just don't leave it there too long, or it will go purple.
Use a blue lightening powder instead of purple if your want silver or grey hair instead of just white, or use a blue toner instead of purple. You can also apply a grey or silver hair dye after you've bleached your hair out to white.
If your hair is very thin or fragile, use a 20 volume bleach, or consider not doing it because some of your hair will come out after the last bleaching process. If your hair is longer than chin-length, you'll need three or four bleaching kits for one bleaching session.
Don't bleach your hair if you've recently had it chemically permed. Wait at least three weeks after a perm.