How do I get my hair back to its natural color?

if you know what boxed color would match your hair, you could dye it cheaper at home than at a salon. but if you dont really know what youre doing, i reccomend a salon. explain the situation and tell them youd like to go back to plain black. im sure they will just dye it totally black for you, but their dye tends to be more high quality and they know what theyre doing (in case you dont, i really dont know your experience (: )