What is a good way to get and keep a squirrel out of your house?

A squirrel has made a home for itself in my house. He got in through a vent (which he broke to get in) and is actually between the outside roof and the inside ceiling. I hear him scurrying around up there. We tried putting a (no kill) trap, but he somehow avoided getting trapped and got the food anyway. We tried calling an exterminator (last resort, we really do not want to kill him if we can avoid it) but they said all they do is put a trap also. So is there anything that we can put in there (something with a smell that he won't like maybe?) that will make him leave and stay out?





(And please, no stupid ideas like 'get a gun and shoot it, that is just not possible and we are trying to to hurt it.)What is a good way to get and keep a squirrel out of your house?
I use some stuff from Lowes called Shotgun Repels All to keep critters out of my garden, if you can get into your attic and sprinkle some around it might work. I know it keeps them out of my garden along with rabbits, coons, skunks, possums, etc. As you can tell by the varmints, I live in rural America.What is a good way to get and keep a squirrel out of your house?
My first idea was to try to find the main ideal of entrance for the squirrel and try to seal it. But, any of your ideas should work as well.
BB gun