How do you kick someone out of your apartment that isn't on the lease?

Basically a friend.roommate moved out and so my other roommate said i have this friend that can move in and pay the portion that the old roommate left us stuck with. So the dudes been living with us for seven months and has only paid rent three times. We came in the other day and found the entire place stinking of marijuana. He had a friend over that was completely a stranger to us that had brought it over to smoke with him. I don't do drugs nor do I want the crap in my apartment to where a freeloader gets to just chill and use all of the peoples stuff in the house. He has no job, no car, nor is he looking for them. I think hes a bum and want him out. We had a conversation about it today and it turned into a huge loud and embarring argument. I told him I wanted him out within the next week and the dude argued about it and a fight almost broke out. How do I get him out within the next week without destroying his face?