A reusable water bottle. The can opener. The coffeemaker. Some kitchen items — particularly those that don't always seem dirty — are often overlooked when it comes to regular and thorough cleanings. Check out this list of surprising dirt-and-germ hiding spots and find out how to wash them properly.

How dirty could a water bottle possibly be? It only comes into contact with clean water and germs from your own mouth, right? The problem is that water bottles harbor the very conditions — humidity plus time, plus occasional heat (like when you leave the bottle in your car) — that favor the growth of bacteria, molds and yeasts. And a quick rinse at the end of the day isn't enough to get rid of them. Instead, wash your bottle and its cap daily with warm, soapy water, using a long-handled brush to reach the bottom and inside the cap. Or, use the dishwasher if your bottle is dishwasher-safe. And be sure to air-dry thoroughly, leaving the bottle uncapped until you refill it for its next outing.

Ever pull out a load of dishes to find it coated with a layer of baked-on grit? The culprit is usually a clogged filter — that new-fashioned addition that makes modern dishwashers so quiet (older models employ a louder, garbage-disposal-type technology that grinds up bits of food). To clean the filter, check your owner's manual. You'll typically find the filter at the bottom of the dishwasher. Remove the bottom rack, then unscrew the filter in a counterclockwise direction. Pull it out gently, along with any flat mesh filter that it fits with. Check the sump (the cylindrical hole where the filter goes) and remove any chunks you find there. Then submerge the filter pieces in a sink filled with warm soapy water and scrub away dirt with a damp, soapy soft cloth or sponge (the parts are delicate, so hold back the abrasive materials and elbow grease). If there is any oily film or residue over the pieces, pour boiling water directly over them to remove it. Many dishwasher manufacturers recommend cleaning out the filter twice a year, but if yours needs it more often, you'll be the first to know — when those dishes stop coming out nice and clean. 

Although you'd think a coffeemaker would be germ-free (boiling water runs through it, after all), the heat and humidity inside it help bacteria thrive. A 2011 study by NSF International, an independent public health and safety organization, found that a coffeemaker reservoir was one of the most-germ-laden spots in the home — ahead of doorknobs and even the handle on the toilet. NSF recommends following the manufacturer's instructions for daily cleaning, plus doing a monthly vinegar treatment: Pour white vinegar into the reservoir and let it stand. Then run the coffeemaker with fresh water until the aroma of the vinegar subsides.