If possible, keep it in a garage. If no garage, use heavy garbage cans with tight fitting lids. Usually a squirrel in the chimney has fallen in by accident and has a difficult time climbing out. Try lowering a thick, heavy rope or knotted sheets, so the animal can climb out. When gone, cap chimney.
Owls are their natural enemy and predator.
Also use moth balls around the perimeter of attic. Stake the own with light near the den of skunk. Turn light on at dusk and off in the morning. Move owl and light every other day to prevent skunk from becoming used to it. Also, place ammonia soaked rag part way into hole, leaving enough room for animal to exit.