Of the 45 million Americans who have some skin ink, roughly nine million of them wish they didn’t. That’s why laser tattoo removal has become big business. The process works by delivering short-pulse bursts of energy to the skin in billionths or trillionths of a second, lightening and eventually removing pigment. (Fun fact: Green and blue are the hardest colors to erase.) It typically takes a lengthy series of sessions and can result in scarring, but new technologies are getting faster, more effective and less damaging.