By now, you’re well aware that hair masks can make your strands smoother and shinier, but are you utilizing them to their full potential? Luckily for you, Blake Lively is sharing her brilliant hair-mask hack, and it won’t cost you a cent. In an interview with PopSugar, the actress explains that she never fully rinses them out: “I rarely use a conditioner. I always use a mask, so I always rinse it out and leave like 5% of it in. I feel like my hair drinks it up.” So for lively locks (pun totally intended), let your mask double as a leave-in treatment. Our tip: Make sure to rinse it off your scalp, so your hair isn’t weighed down and your dry ends reap all the benefits.