Even if you routinely scrub the inside of your fridge and oven, it's still not enough. Pull your freestanding appliances away from the wall and you may be in for an unpleasant surprise. With refrigerators especially, you can expect to see dust from the fridge’s coils (remember to clean those too, with your vacuum’s crevice attachment), plus errant spills and leaks. Mop up the area as you would normally and make sure to let it dry completely before replacing the appliances.

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You hold it up to your face every day -- often multiple times a day -- but how often do you clean your phone? Here's a wake-up call: Your phone has more germs than your toilet seat or the bottom of your shoe! Give it a few swipes with an antibacterial wipe every now and then.

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Many remote controls contain the virus that causes the common cold (our unofficial study shows that a large majority contain Doritos crumbs and sticky Diet Coke residue too). Using antibacterial wipes or a napkin moistened with rubbing alcohol to clean it about once a week should do the trick. Use cotton swabs to get into those little crevices. Oh, and all of this applies to your computer keyboard too; just take a look at it. Closer...ew, right?

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Ever get up on a chair to, say, change a lightbulb and notice that there's so much dust on the blades of your ceiling fan that you could write your name in it? Rule of thumb: If you can't see it in your daily life, it's probably filthier than you think. Use microfiber cloths in lieu of a feather duster so you can capture the dust instead of spreading it around.

Someone in our office, who shall remain nameless, recently packed for a move and noticed -- upon disassembling her Keurig coffeemaker -- that the plastic water reservoir was kind of...yellow. "Who knows how long we’ve been drinking from it that way!" she said. The discoloration was most likely the result of mineral residue. The best way to clean up this gunk is to fill the reservoir with a mixture of equal parts water and white vinegar, and then run the pot without any coffee grinds. Do it a second time for extra-dirty appliances.

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You may not think to pull your stove knobs off very often, but once you do, you might wish you hadn't. The knobs are designed to come off easily so you can clean all the grime behind them using a gentle cleanser like vinegar. Make it a part of your regular stove-cleaning routine and you won’t have to confront built-up gunk.

You know that phrase "sweep it under the carpet"? Yep, this household spot has become synonymous with hidden dirt. It’s actually amazing how much debris can accumulate under a rug in a short period of time. Pull yours up the next time you’re vacuuming it and see for yourself how many allergens are living under there. Ick!

This one’s a common frustration. Baseboards may mask the area where your walls meet your floors, but they also effectively serve as little ledges for dirt (and hair!) to settle. If you don’t feel like getting on your hands and knees and scrubbing away Cinderella-style, use the crevice tool on your vacuum instead.

In general, anything you can't see (unless you’re super-tall) is probably way dirtier than you think. Get up on a stepladder and check out the tops of your cabinets. It may not be pretty, but a simple dusting should do the trick.

We saved this one for last because of the surprise factor. Even a visibly clean kitchen sink may not really be clean. In fact, kitchen sinks often harbor more bacteria than the floors -- or even a toilet...in a public bathroom! -- according to an associate professor of microbiology at The University of Arizona. (Blame it on all the bacteria from raw meats and veggies.) So in addition to rinsing down the sink, disinfect it. If you don't feel safe using diluted bleach (although many experts say it’s fine), try tea-tree oil, an essential oil with disinfectant properties.