Cigarette smoke residue can take years to leech out of walls, carpeting and air conditioning ducts -- if it ever comes out at all. You might think your trusty olfactory stink-o-meter would know right away that a smoker has been at work spewing carcinogens all over your soon-to-be (maybe) home, but that might not be true. The strong smell of Febreze, ammonia, bleach and even baking cookies (how sneaky) can disguise the wicked stench. One humid afternoon soon after the sale, the rank aroma of spent ciggys could start oozing toward your unsuspecting family. Be proactive and beat the butts. Make sure you're buying a non-smoking home.