You sure can! Simply harvest mint leaves, wash them, pat dry and allow the mint to rest in the open in a place where you’ll have lots of air circulate and ventilate, until you’re able to dry the leaves properly. You can also use a herb drying rack for this purpose if you want to.  If you’re planning on drying the herbs for a longer period, you may want to cover them up with a paper bag to keep them from attracting any dust.