Dye your hair when it is dirty or clean?
Dye it a color when it is clean. However, read the label on your
hair dye thoroughly. Some dyes require a wash after you dye to wash
the dye out. In this case that means you will wash your hair twice
in one day. Make sure you use a leave in conditioner in addition to
your conditioner so that your hair gets some moisture back.
Bleaching is ok when your hair is dirty. However, I wouldn't
recommend letting more then 1 day go by unwashed before bleaching
or you may risk uneven color.