Hair dye is filled with chemicals that can burn your skin. Dye your hair with a hair coloring brush without touching your scalp. The brush allows you to apply dye to small sections of your hair, starting with the roots and working your way down to the bottom of each section. The person using the brush should move slowly near the roots, taking care not to touch the scalp.
Divide dry hair into thin sections, about 1 centimeter thick and a few inches wide, with the comb. Begin at the top of the head and work with one section at a time.
Place a piece of aluminum foil under the section you're working with, as close to the scalp as possible. The foil should be wide enough to wrap around the section and about 6 inches long -- enough to lay flat against the scalp and protect it from the chemical dye.
Brush the dye onto the section, painting it flat against the piece of aluminum foil. Do not paint the skin or scalp, but paint as close to the roots as possible. Work your way all the way down the person's hair. Make sure their neck and clothing is protected with a salon cape.
Fold the aluminum foil over the painted section and repeat the process for the remaining sections. The aluminum foil will hold the dye away from the scalp until you are ready to rinse.