Yep, do them first on leg day for the reason CoolColJgave. A lot of routines will tell you to hit the squat rack 1st, but cleans stimulate the CNS more, and they are a movement where skill and form and technique are everything. If you're slightly tired when squatting, you cal always dig down deep for that little something extra because any moron can perform a squat, it just takes balls and desire, if you're tired during cleans your form will fall apart and your body just won't do what you tell it to.