Home is where the heart is -- not to mention the dirt, dust, bacteria and mold. "People typically only realize how filthy their house is when they move out," says Richard Symes of Clenz Philly, an eco-friendly home and commercial cleaning service in New Jersey and Philadelphia. "Most people clean what they can see, but there's a lot more to cleaning a home than just wiping down your bureau."

Here are the top neglected spots, the most powerful cleaning tools (that you're probably not using) and how often you need to scrub up. The payoff is better air quality, fewer allergy symptoms, a house you can show off to the neighbors, and best of all, peace of mind.

5 Places to Look

1.  Up, down and underneath
Look high -- in ceiling corners, on top of shades, blinds and picture frames, and on the blades of ceiling fans -- to find neglected dust. Look low -- under baseboards, under furniture and in the corners of kitchens and bathrooms -- to find colonies of dust bunnies and layers of dirt and grime.

2.  Bedding
Millions of organisms live in your mattress. Their dead cells and feces are the No. 1 cause of allergies in a home, says Symes. Get your bed and pillows steam-cleaned once a year to sterilize your sleeping environment.

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