Can't I just say "I wash my hair in the shower" without "out"?
Native speaker’s answer
Rebecca
Yes, you are correct. Normally, we would say "I wash my hair in the shower." However, the clue for why Lauv includes "out" is found in the lyrics that follow: "but something still remains." When we say "wash out," we are usually referring to the specific act of washing away the residue of some substance, usually something like shampoo or conditioner. Thus, you often see sentences like "wash out the shampoo" or "wash out the hair dye." When Lauv says that "something still remains," he is alluding to a strange feeling still remaining on his head, which we later find out to be the memories of his lover. This is why he says "wash my hair out," as the next line proves that he metaphorically wasn't able to rinse his head completely clean. Ex: The instructions say to wash out the hair dye after 20 minutes. Ex: I got a little wine on my sweater, but I was able to wash it out with bleach.
