Every day at wikiHow, we work hard to give you access to instructions and information that will help you live a better life, whether it's keeping you safer, healthier, or improving your well-being. Keep in mind, though, that with very dark hair, it may take multiple treatments to bleach it completely. Wave spray adds texture to your hair and can be purchased at your local drug store or online. Read on to learn the best way to cover grays on dark hair. To boil it down, there are essentially two different types of color your colorist can use to cover gray hair—demi-permanent or permanent. This image may not be used by other entities without the express written consent of wikiHow, Inc.