Did you know that dry shampoo was formulated for the elderly or sick people who couldn't wash their hair? How about the fact that, back in the day, like way back, people shampooed only once every six weeks?
In a video by Mental Floss, host Craig Benzine reveals 16 facts about shampoo that you probably didn't know.
Like the fact that human scalps are waterproof and shampoos de-waterproof it to bring up dirt and oil.
Because of this 'poo capability, it can also clean grease stains from shirt collars.
Oh, and Japan has a shampoo robot to test new formulas.
Check out the rest of the facts in the video below, then, go wash your hair.